Germany's foreign minister on Saturday said the next U.S. administration should not expect significantly greater participation by the German army in Afghanistan.

"Obviously some would like us to do more. We have stretched ourselves quite a bit. Our resources are not unlimited," Frank-Walter Steinmeier said in a speech at Harvard University.

He was referring to any request by a future U.S. government for a bigger commitment by its European allies in Afghanistan.

The NATO-led International Security Assistance Force (ISAF) has some 43,000 troops in Afghanistan fighting Taliban militants, who have regrouped since Afghan and U.S.-led forces toppled the hard-line Islamist movement from power after the Sept. 11 attacks.

U.S., British, Canadian and Dutch troops are engaged in the bulk of the fighting in southern and eastern Afghanistan. Other NATO members, notably France and Germany, have resisted U.S. pressure to allow their soldiers to operate outside the relatively safe northern part of the country.

Germany has roughly 3,300 troops in Afghanistan, and a strong majority of Germans oppose any deployment to the south.

'ENGAGE WITH RUSSIA'

Steinmeier also commented on the recent meeting between U.S. President George W. Bush and Russian President Vladimir Putin and urged the United States not to isolate Russia.

"A safer world also means that America and Europe must engage with Russia. Both the NATO summit and the subsequent meeting between Bush and Putin have shown that we all - Europeans and Americans - share a vital strategic interest in keeping Russia as an active constructive partner," he said.

Steinmeier had his first talks on Friday with Democratic presidential candidate Barack Obama, and he met with the foreign policy advisers of all three candidates - Obama, his Democratic rival Sen. Hillary Clinton and Sen. John McCain, the presumptive Republican nominee.

The presidential election in November will determine who succeeds Bush in January. In the campaign, both Obama and Clinton have expressed concerns about international free trade agreements.

"In Europe and the United States there are siren songs of protectionism coming from left, right and center. I see this with great concern as we all know: siren songs are very tempting - and very dangerous," Steinmeier said.

Steinmeier called for a revitalized alliance between the United States and Europe.

"What we need today: new concepts, a revitalized alliance and particularly renewed American leadership in the world," he said. "To use 'smart power,' America with its global reach needs allies, and Europe for its global contributions, needs America."