Germany will start to withdraw its troops from Afghanistan at the start of 2012, cutting its contingent to 4,900 soldiers from 5,350, the government said on Thursday.

It is the first reduction since German troops joined the NATO-led International Security Assistance Force (ISAF) in Afghanistan almost a decade ago.

German Foreign Minister Guido Westerwelle and Defence Minister Thomas de Maiziere told party leaders in a letter that troop numbers could be reduced further to 4,400 within a year should the security situation allow.

Germany's lower house of parliament will vote on a new mandate for the German troops when the present one expires in January 2012. The ISAF is set to withdraw combat troops from Afghanistan by the end of 2014.

(Reporting by Sabine Siebold)