The United States called on southeastern Europe on Wednesday, including aspiring NATO members, to send more troops to fight the insurgency in Afghanistan, Reuters reported.

As the conflict with Taliban fighters has escalated, U.S. Defense Secretary Robert Gates has increasingly looked for troop contributions from outside NATO.

"As the situation on the ground in Iraq continues to improve, I urge you to consider sending your military forces to Afghanistan," Gates told a meeting of the Southeastern Europe Defense Ministerial, a group of 12 countries that includes Italy, Turkey, Ukraine, Romania and Macedonia.

"Your assistance will not only help Afghanistan better protect and care for its citizens, it will also reinforce your important role in ensuring peace and stability around the world," he said.

Violence in Afghanistan has soared for more than two years and the Pentagon chief has repeatedly asked NATO members and others to send troops, equipment and money to the war zone. Still, NATO commanders say they need another three brigades, or about 10,000 to 12,000 troops.

While the United States is likely to fill that requirement next year as the Pentagon starts to shift focus to Afghanistan from Iraq, U.S. officials worry NATO allies will see that as an excuse not to meet pledges to commit more resources.

"I want to make sure that everybody understands that the increases in U.S. forces are not seen as replacements for NATO contributions. They`re reinforcement," Gates told reporters traveling with him this week. He will raise the issue at a NATO meeting in Budapest on Thursday.

The United States has 33,000 troops in Afghanistan, including 13,000 under the NATO mission. America has the most forces there of any country, followed by Britain with about 8,000 troops.

All members of the southeastern Europe defence group except Bosnia have troops in Afghanistan, totaling 5,000. Among them, Italy has 2,350 followed by Turkey with 800, Romania with 725 and Bulgaria with 460, according to NATO data.

Macedonia, which said on Tuesday it would pull its 77 troops out of Iraq, is considering sending more forces to Afghanistan, according to the U.S. Ambassador to Macedonia, Philip Reeker.

"Macedonians have indicated an openness, as their Iraq deployment comes to an end, to looking at augmenting the forces already in Afghanistan," Reeker told reporters. Macedonia has 135 troops in Afghanistan.