U.S. Defense Secretary Robert Gates says he sees a chance for better relations with Russia with a new president in the White House.

However, he warned that Moscow is trying to "have it both ways" by offering help in Afghanistan while undermining U.S. efforts there at the same time.

Gates signed a new military cooperation agreement with Poland on Thursday, formalizing ties between the special forces operations of both countries. Gates praised Poland''s willingness to send troops into harm''s way, including about 1,600 in Afghanistan.

"As an old Cold Warrior it is a true honor to be able to sign this document on behalf of the United States," Gates told Polish Defense Minister Bogdan Klich.

Poland is one site for a planned U.S. missile shield system that Russia has aggressively protested, but neither Gates nor Klich mentioned it during the brief signing ceremony.

Rhetoric on the missile system grew heated last year, and was compounded by U.S. outrage over Russia''s invasion of Georgia last summer. Both the U.S. and Russia have made overtures to ease the tension since President Barack Obama''s inauguration. The United States hopes it might work out new assurances to Russia that the system is aimed at Iran and not at Moscow.

"I am hopeful that with a new start that maybe there are some opportunities with the Russians that we can pursue," Gates said as he flew to Europe for a gathering of NATO defense ministers.