MOSCOW — High-level talks today between America and Russia failed to bridge major differences over American plans for a missile defense system in Europe and a range of strategic arms issues.

After a series of tense meetings that began with a blunt rebuff from President Putin of Russia, Secretary of State Rice and Defense Secretary Gates appeared to have been unable to turn around Moscow’s opposition to missile defense.

Ms. Rice and Mr. Gates brought several new detailed proposals to the table meant to ease Russian concerns that the system would be aimed at Moscow, but the pair was unable to convince Foreign Minister Sergey Lavrov or Defense Minister Anatoly Serdyukov.

“We see two serious problems with these proposals,” Mr. Lavrov told reporters at a four-way news conference following the talks.

He said the two sides still disagree about the nature of the missile threat to Europe and that the Bush administration refuses to freeze its deployment plans while the issue is discussed.

“There is no agreement on this,” Mr. Lavrov said. He said that while the initial American plan to place elements of the system in Poland and the Czech Republic were small, it could grow to become a threat to Russia’s deterrent force. “There is a potential threat for us here.”

Mr. Serdyukov agreed.

“The principal thing to which we did not agree today is the deployment of anti-missile elements which have an anti-Russian character and which are to be placed in Europe,” he said.

Ms. Rice said the ideas that she and Mr. Gates presented are “conceptual at this point” and would be handed to experts to consider further. The two sides plan to meet again in Washington in about six months.

“I know that we don’t always see eye-to-eye on every element of the solutions to these issues, nonetheless, I believe we will do this in a constructive spirit, that we will make progress during these talks as we continue to pursue cooperation,” Ms. Rice said.

Mr. Gates said that one idea is to have Russian personnel stationed at each missile defense site to improve coordination and openness with Moscow.

Neither Messrs. Lavrov nor Serdyukov appeared impressed with the suggestion.

The day got off to a rocky start with Mr. Putin warning Washington to back off European missile defense, which he appeared to mock, or risk harming relations with Moscow. He also threatened to pull out of a Cold War-era treaty limiting intermediate-range missiles unless it is expanded.

“We may decide someday to put missile defense systems on the moon, but before we get to that we may lose a chance for agreement because of you implementing your own plans,” he told Ms. Rice and Mr. Gates in Russian.

He also urged the Bush administration not to force its plans on countries in eastern Europe.

“We hope that in the process of such complex and multifaceted talks you will not be forcing forward your previous agreements with eastern European countries,” the president said.

The Pentagon plans to install 10 missile interceptors in Poland, linked to a missile tracking radar in the Czech Republic. The Pentagon says the system will provide some protection in Europe and beyond for long-range missiles launched from Iran, but Russia believes the system is a step toward undermining the deterrent value of its nuclear arsenal.

Russia sees the American missile defense plan, which Washington describes as a hedge against the threat of missile attack from Iran, as a worrisome step toward weakening Russian security. It has been a long-standing dispute, and Mr. Putin’s remarks seemed to raise the level of tensions.

After keeping Ms. Rice and Mr. Gates waiting for 40 minutes, Mr. Putin began the session with a lengthy monologue in which he also said Russia might abandon its obligations under a 1987 missile treaty with America if it is not expanded to constrain other missile-armed countries.

Referring to the Intermediate-range Nuclear Forces treaty that was negotiated with America before the breakup of the Soviet Union, Mr. Putin said it must be applied to other countries, but did not mention any by name.

“If we are unable to obtain such a goal … it will be difficult for us to keep within the framework of the treaty in a situation where other countries do develop such weapon systems, and among those are countries located in our near vicinity,” he said.