Transfer round-up: 24-30 January

Republic of Ireland striker Robbie Keane said he "can't wait to start playing football" after leaving Tottenham Hotspur FC for West Ham United FC, who had a busy week.

As the European domestic transfer window nears its close, keeps you posted with stories on all major signings involving clubs in the UEFA Champions League and UEFA Europa League while this regularly updated round-up covers the other significant moves before the 31 January deadline.

The Premier League's bottom club, West Ham United FC, have made their fourth signing of the transfer window, bringing in Robbie Keane from Tottenham Hotspur FC. The 30-year-old striker joins on an initial six-month basis which will be extended by two years should West Ham avoid relegation. "I am ready to help West Ham United stay in the Premier League," said Keane, who has scored 46 goals in 104 appearances for the Republic of Ireland.

West Ham have also signed Demba Ba from TSG 1899 Hoffenheim, the Senegalese striker signing a contract until June 2014 after the clubs agreed an undisclosed fee. "It was a long story, but now I'm happy because it had a really good end and I'm glad to be here," said the 25-year-old. "I'm going to give everything to West Ham United."

Manager Avram Grant has likewise brought in midfielder Gary O'Neil, 27, from second-tier side Middlesbrough FC, also for an undisclosed fee. O'Neil has accepted a two-and-a-half-year contract at the London club, who sit two points from safety. "It is nice to be back in the Premier League and play at the top level, which everyone wants to do," he said. "I am London-born so it is good to come home."

Wilfried Bony, who has scored five UEFA Europa League goals this term, has left AC Sparta Praha to sign for Vitesse on a three-and-a-half year contract. The 22-year-old striker moves to the Eredivisie having scored 21 goals in 58 league appearances during his three seasons in Prague.

Sunderland AFC have completed a double swoop for midfielders Sulley Muntari and Stéphane Sessegnon of FC Internazionale Milano and Paris Saint-Germain FC respectively. The 26-year-old Muntari, who has agreed a six-month loan deal with the Black Cats, won the treble in his second season at Inter last year but, having started just one Serie A match this term, opted to return to England, where he won the FA Cup with Portsmouth FC in 2007/08.

Sessegnon, also 26, has arrived for €7m on a three-and-a-half year deal. The Benin playmaker joined PSG from Le Mans UC 72 in summer 2008, helping the capital club reach the UEFA Cup quarter-finals in his first campaign and scoring eight goals in 77 Ligue 1 appearances. "Stéphane can play on the left, on the right, through the middle – he's lightning quick and he's a match-winner," said Sunderland manager Steve Bruce.

Nigeria striker John Utaka is back in France after signing a two-and-a-half year contract with Montpellier Hérault SC. The 29-year-old former FC Lens and Stade Rennais FC forward has been at Portsmouth FC since summer 2007 but now returns to Ligue 1 for an undisclosed fee.

Arsenal FC's Mexican striker Carlos Vela will spend the remainder of the season on loan with Premier League rivals West Bromwich Albion FC. The 21-year-old scored twice in four UEFA Champions League group stage games in the autumn. West Brom coach Roberto di Matteo said: "He is a new attacking option for us and can play both centrally or wide. He also has great technical ability and pace."

Struggling AS Monaco FC have taken experienced midfielder Mahamadou Diarra on a free transfer from Real Madrid CF. The 29-year-old Malian international, a title winner on four occasions with Olympique Lyonnais in his previous spell in Ligue 1, has agreed a deal until the end of the season with the Principality club, who are one off the foot of the French top flight. Monaco coach Laurent Banide said: "Our squad needed a character like him."

Former England Under-21 international Curtis Davies has joined Birmingham City FC from arch-rivals Aston Villa FC, with the 25-year-old signing a three-and-a-half year contract at St Andrew's. Villa manager Gérard Houllier said: "He is a nice lad but, as you know, we have four centre-backs in James Collins, Richard Dunne, Carlos Cuéllar and Ciaran Clark. He was not getting enough time to play. I understand that."

Hoffenheim have signed Dutch international left-back Edson Braafheid from FC Bayern München. The 27-year-old made just 12 league appearances for Bayern after joining from FC Twente in 2009, and was loaned out to Celtic FC for the second half of last season. He has agreed a contract until June 2014 at Hoffenheim, where he will join Netherlands team-mate Ryan Babel, who arrived from Liverpool earlier this week.

Scottish Premier League leaders Celtic FC have completed the signing of Kris Commons from English second-tier side Derby County FC. The 27-year-old Scotland midfielder has accepted a three-and-a-half year deal with the option of a further 12 months after both clubs agreed an undisclosed transfer fee.

Bundesliga outfit VfL Wolfsburg have filled the hole created by Edin Džeko's departure to Manchester City FC earlier this month by bringing in Dieumerci Mbokani on loan from Monaco until the summer. The arrangement for the 25-year-old DR Congo forward − who has scored once in ten Ligue 1 outings this term − can be made permanent at the end of the campaign, when Srdjan Lakić will arrive on a free from 1. FC Kaiserslautern. Lakić has struck an impressive total of 11 goals in 17 Bundesliga appearances this season.

Departing Wolfsburg, however, is Italy centre-back Andrea Barzagli, who has signed a contract until June 2013 with Juventus. A FIFA World Cup winner in 2006, the 29-year-old left US Città di Palermo for Wolfsburg in 2008, picking up the Bundesliga title during his first season at the club. Juventus have paid a reported €300,000 for the defender, who made his Serie A debut under the Turin side's coach − Luigi Delneri − at AC Chievo Verona in 2003. That fee could rise to €600,000 depending on where La Vecchia Signora finish in the table.

Midfielder Michael Fink has returned to Germany to join the Bundesliga's bottom club, VfL Borussia Mönchengladbach, on loan from Turkish side Beşiktaş JK until the season's end. The 28-year-old has made just five league appearances in his second campaign in Turkey but Gladbach sporting director Max Eberl said: "Michael Fink is an experienced player in the holding midfield. He knows the Bundesliga from his time with Arminia Bielefeld and Eintracht Frankfurt and we are pleased that he has decided to join us."

Swiss international Valon Behrami has left West Ham United FC to return to Serie A with ACF Fiorentina. The former S.S. Lazio midfielder, 25, scored four goals in 58 league games for the Hammers, but spent a long spell on the sidelines in 2009 after sustaining a serious knee ligament injury. Behrami, capped 28 times by Switzerland, has agreed a three-and-a-half year contract in Florence.

FC Dnipro Dnipropetrovsk have signed FC Basel 1893 defender Samuel Inkoom and Brazilian playmaker Giuliano for undisclosed fees. The 20-year-old Giuliano played for Paraná Clube and SC Internacional, and was in the Brazil side that lost to Inkoom's Ghana in the 2009 FIFA U-20 World Cup final. The 21-year-old Inkoom also played in last summer's FIFA World Cup finals, and said: "Dnipro coach Juande Ramos is rightly regarded as one of the best in the world. I am ready to play in any position he tells me."

Kew Jaliens has left AZ Alkmaar on a two-and-a-half year contract for Wisła Kraków. The 32-year-old defender, who has played over 380 matches in his homeland for Sparta Rotterdam, Willem II and AZ, joins a Wisła team coached by compatriot Robert Maaskant. "I wanted to play abroad," said Jaliens, who won the last of his ten caps for the Netherlands in October 2007. "I've watched some of Wisła's matches on the internet and was amazed by the fans."

Chelsea FC's 19-year-old forward Gaël Kakuta has joined west London neighbours Fulham FC on loan for the remainder of the season. The French Under-19 international played in five of Chelsea's six UEFA Champions League group stage games this season, and also made five Premier League appearances, four of them as a substitute.

Netherlands forward Ryan Babel, 24, has ended his three-and-a-half year stay at Liverpool FC by signing with Bundesliga outfit TSG 1899 Hoffenheim until summer 2013, with the option of a further season. Babel, formerly of AFC Ajax, added: "I am looking forward to my new challenge at Hoffenheim. My first impressions are absolutely positive. I hope to be able to integrate into the team as quickly as possible."

Teenage Latvia forward Deniss Rakeļs has left his home country and joined Polish outfit Zagłębie Lubin. The 18-year-old has agreed a three-year deal with Zagłębie after topping the Virslīga scoring chart with 18 goals for third-placed SK Liepājas Metalurgs in 2010. Capped twice, the promising striker had been tipped to sign for FC Rubin Kazan in Russia but instead opted for the Ekstraklasa. "I consider this move a serious step forward," said Rakeļs. "The Polish league is much stronger than the Latvian and to progress you have to play at a high level."

David Elm has returned to Sweden with IF Elfsborg after failing to gain a regular first-team place with Premier League club Fulham FC. The 28-year-old elder brother of AZ Alkmaar's Rasmus Elm and SC Heerenveen's Viktor Elm had arrived at Fulham from Kalmar FF in 2009, but scored just once in ten league games. "I wanted to come home," said Elm. "The last six months have not been great."

Promoted Russian Premier-Liga team FC Volga Nizhny Novgorod have landed Georgia defender Lasha Salukvadze on a free transfer from UEFA Europa League contenders Rubin Kazan. No further details of the transfer have been released. The 29-year-old centre-back played 91 top-flight matches for Rubin after joining in 2005 from FC Dinamo Tbilisi.