Secretary of State Hillary Clinton says she is encouraged by the response of American allies to the Obama administration's appeal for additional troops to supplement the boost in U.S. forces in Afghanistan. Clinton is in Brussels for meetings Friday with foreign ministers of NATO and other contributors to the International Security Assistance Force in Afghanistan, ISAF.

Clinton spent much of Wednesday and Thursday explaining President Obama's new Afghan policy to members of the U.S. Congress, and will do more of the same in Brussels with her counterparts from NATO and the other contributors to the 43-nation ISAF force.

Administration officials have said they hope the allies can supplement the United States pending 30,000 troop increase in Afghanistan with an additional ten thousand troops of their own.

Initial indications from NATO are that the collective allied increase may only be half that - perhaps five to seven thousand troops.

But Clinton, speaking to reporters on her plane bound for Brussels, said she had spoken to as many as 25 fellow foreign ministers in the last week and said she was encouraged by what was, overall, a positive response. "There's an understanding about the importance of the mission that the President has described. There is a desire to be able to explain it to the publics of various countries, and to make sure that in coalition governments the political stars are in alignment to be able to announce additional commitments. We feel good about it," she said.

Clinton suggested that because of the need in some cases for parliamentary approval for troop pledges,  announcements of new commitments may not come immediately.

She said she anticipated skeptical questioning in Brussels, much like that she and other top officials encountered in U.S. Congress, about the President's announcement of a July, 2011 target date for the beginning of a U.S. troop withdrawal.

Citing misunderstandings about the withdrawal target, Clinton said the United States does not contemplate any precipitous action.  "Starting in 2011, we will be prepared for a responsible transfer of security responsibility to the Afghan security forces based on the conditions as we evaluate them at that time. Now, that doesn't mean we're going top get to 2011 and jump off a cliff. It means that we're going to be as careful and deliberative as necessary, but that we expect by 2011 to be able to pass off the responsibility for security to an improved, larger Afghan security force," she said.

Clinton said the training of Afghan forces, which she suggested had been a secondary priority during the Bush administration, will be stepped-up through what she termed partnering in combat.

In addition to multi-lateral meetings with NATO and ISAF contributing countries, Clinton has a series of bilateral meetings Friday with, among others, Russian Foreign Minister Sergei Lavrov, in Brussels for a meeting of the NATO-Russia Council.

Clinton and Lavrov are expected to discuss the drive for an agreement this month on a new U.S.-Russia strategic arms reduction treaty, and Iran's defiant response to the International Atomic Energy Agency's recent censure of Tehran for concealing its uranium enrichment plant near the city of Qom.