Russian Foreign Minister Sergei Lavrov says U.S. missile defense plans for Europe remain an irritant in relations with the United States.

Lavrov said at the Russian embassy in Washington Tuesday that Moscow believes the U.S. plans threaten Russian security and could force Russia to respond militarily.

Missile defense may dominate Lavrov's talks with President Barack Obama at the White House Wednesday, and his meeting with Secretary of State Hillary Clinton.

Other issues on the White House agenda likely will be Russian efforts to mediate in Libya, and Moscow's desires to join the World Trade Organization.

The United States has long said Russia has nothing to fear from plans to build a missile defense system in Europe. It says the system is aimed at countering a possible attack from Iran or North Korea, and is not aimed at Russia or anyone else.

Mr. Obama scrapped a proposal by former President George W. Bush to concentrate missile defense in Poland and the Czech Republic, near Russia's borders, in favor of what is being called a phased-in approach. It would involve sea and land-based interceptors.