MOSCOW - Russia's foreign minister yesterday accused the United States of backtracking on proposals for missile-defense cooperation, and he rebuked Washington on other divisive security issues.

The remarks by Foreign Minister Sergey Lavrov set a tough tone for an expected meeting tomorrow in Brussels with Secretary of State Condoleezza Rice, and they follow parliamentary elections that strengthened President Vladimir V. Putin, who has made criticism of American foreign policy a mantra.

Underlining a deep rift over U.S. plans to deploy missile-defense installations in former Soviet satellite states of Central Europe, Lavrov detailed Russian allegations that Washington has gone back on compromises promised when he met with Rice in October.

The United States has withdrawn a proposal for constant Russian monitoring of planned U.S. missile-defense facilities in Poland and the Czech Republic and has rejected the idea of jointly evaluating threats that would trigger activation of the system, he said.

"There has been a serious rollback from what we were told," Lavrov said.

The United States says the installations in the two nations, now NATO members, would counter a looming Iranian threat. Moscow disputes Washington's view of that threat and says it believes the real aim is to weaken Russia.

Putin this year offered an alternative involving joint use of Russian radar and urged Washington to shelve its plans. The United States welcomed the offer but pushed ahead with its plans while continuing compromise talks with Russia.

"We are, frankly, disappointed," Lavrov said of formal proposals the United States submitted late last month. The proposals "added nothing new to the situation that existed before" the visit by Rice and Defense Secretary Robert M. Gates, he said.

Lavrov suggested that in October the United States had said Russian personnel could be stationed permanently at the sites to monitor their operations. The formal proposals, he said, offer only intermittent visits, subject to Polish and Czech approval.

"This is a completely different story from what was proposed to us verbally," he said.

In a nod to Russia's concerns, the United States has offered to hold off activating the missile-defense facilities until a concrete threat emerges. But Lavrov said that under the formal proposals, threats would be evaluated "not jointly but by the United States."

"This is a radical contradiction to our approach," he said.