Russia's foreign minister said Thursday he was surprised by Poland's call for more U.S. troops on Polish soil in response to Moscow's assertiveness, a news agency reported.

RIA Novosti quoted minister Sergei Lavrov as saying that the request by his Polish counterpart, Radek Sikorski, contradicted Moscow's and Warsaw's understanding of security issues in Europe.

"If he did say that, it makes me deeply astonished," Lavrov said.

Sikorski said Wednesday at the Center for Strategic and International Studies in Washington that "we need some strategic reassurance," and that the U.S. could provide it by sending more than the six American troops it now has based in Poland. The minister said that need became clear when Russia and Belarus conducted a military exercise with hundreds of tanks near Poland's border last month.

Sikorski said that when Poland joined NATO 10 years ago, Russia was assured that no substantial NATO forces would be sent to the region. But, the minister said, the security situation has since changed.

Poland also raised concerns about its security when the Obama administration decided in September to scrap a plan to deploy long-range missile interceptors in Poland and a radar system in the Czech Republic.