BERLIN, Germany (CNN) -- Germany insists it will not send more troops to Afghanistan and it will not move them to the restive south, despite a reported request from the United States.
Defense Minister Franz Josef Jung said Friday that the 3,200 German troops already in Afghanistan fulfilled Germany's mandate, and that he felt the country was doing enough to support the NATO mission.
Jung spoke at a news conference after German news outlets reported U.S. Defense Secretary Robert Gates had sent a letter in which he "demanded" greater participation in southern Afghanistan.
Jung did not speak about the letter's contents, but the Sueddeutsche Zeitung newspaper reported the it was "formal and direct" and written in an "unusually sharp tone."
Gates' letter requested a contribution to a reinforcement of 3,200 troops for the NATO mission in southern Afghanistan, the newspaper reported, especially with the helicopter units and paratroopers in the south.
Gates' letter "complained about the split in NATO with nations that deny military operations, and nations that don't take part in the military combat against the Taliban and al Qaeda fighters," according to the paper.
"Gates speaks of a threatening division in the alliance and warns of a loss of reliability," the paper reported. "He describes the overstretching of U.S. armed forces."
Jung said he would not move or increase the number of German troops, who are currently based in the north.
"We've agreed to a clear division of the regions we will cover," Jung said.
He said Germany was already assisting the NATO mission in the south by flying Tornado reconnaissance planes over the area.
"Our emphasis will remain on the north, especially in light of an increased threat level there in the northwestern regions where, when international aid organizations and the army move out, the Taliban have been moving in," Jung said.
Pentagon spokesman Brian Whitman said Gates had sent letters to several defense ministers asking them to provide troops to replace the 3,200 U.S. Marines being sent to Afghanistan.
"He has reached out to many allies who have capabilities that could backfill" the U.S. Marines, Whitman said.
Whitman said Gates was being "frank and direct" in his communications with allies.
The issue of burden-sharing in Afghanistan among NATO countries is becoming a key issue, according to a report this week from the Afghanistan Study Group, co-chaired by retired Marine Corps Gen. James Jones and former U.N. Ambassador Thomas Pickering.
The report said some nations were contributing more to the fighting than others, and that public opposition to the Afghan effort was growing in some nations.
Earlier this week, Canada's prime minister said his country's troops would leave Afghanistan in a year unless another NATO nation sent an additional 1,000 combat troops to the southern province of Kandahar, where Canadian troops are based.
The Canadian presence in Afghanistan has sparked controversy in Canada, with some political parties calling for the troops to come home.
CNN's Frederik Pleitgen and Diana Magnay in Berlin and Barbara Starr at the Pentagon contributed to this report.