West Ham's Czech Republic midfielder Radoslav Kovac has announced he is retiring from international football to concentrate on his club commitments.The 30-year-old scored two goals in 30 matches for the Czech Republic and played at the 2006 World Cup and 2008 European Championship. [LNB]Kovac joined the Hammers from Spartak Moscow on loan in January 2008 and signed a permanent deal in August. [LNB]The Czech Republic failed to qualify for the 2010 World Cup in South Africa. [LNB]Versatile Kovac, who can play in central midfield or defence, has scored once in 11 Premier League appearances for West Ham this season. [LNB]His side are one place above the relegation zone with 18 points from 20 matches.