KANDAHAR (Reuters) - The gradual withdrawal of US combat troops from Afghanistan set to begin next month will be done responsibly and will not expose other coalition and Afghan forces to undue risks, Defence Secretary Robert Gates said on Sunday. General David Petraeus, commander of the 150,000 foreign troops in Afghanistan, will soon make recommendations to President Barack Obama about how many should be withdrawn, following Obamas pledge last year to start bringing US combat troops home. The commitment followed Obamas December 2009 decision to send 30,000 extra US troops in a bid to arrest a growing Taliban-led insurgency. Fighting increased dramatically, particularly in the Taliban heartland in the south, since the last of those extra troops arrived last summer. Pentagon and White House officials are tight-lipped about the size of the initial withdrawal. Obama is expected to announce his decision sometime in mid-July. Gates said great strides had been made in training enough Afghan police and soldiers adequately to allow for the gradual withdrawal that will end with all foreign combat troops leaving.