WASHINGTON (AP) — The Trump administration on Friday rejected as "a non-starter" Russia's stance that a key nuclear arms control treaty be extended without imposing a broader, short-term freeze on U.S. and Russian nuclear weapons.

In a written statement, Robert O'Brien, the national security adviser to President Donald Trump, said the United States had proposed an extension of the New START treaty for one year, in exchange for Russia and the United States capping all nuclear warheads during that period.

"This would have been a win for both sides," he said.

Russian President Vladimir Putin earlier Friday said he could accept a short-term extension of the treaty, but only if it were without conditions.

THIS IS A BREAKING NEWS UPDATE. AP's earlier story follows below.

Russian President Vladimir Putin on Friday made a strong call to save the last existing nuclear arms control pact between his country and the United States, proposing to extend it at least for one year.

Putin's statement comes amid conflicting signals from Russian and U.S. diplomats about the fate of the New START treaty that is set to expire in February unless Moscow and Washington agree on its extension.

While Putin is offering to extend the New START as it is, the U.S. has proposed a broader freeze on all nuclear warheads, including battlefield nuclear weapons that aren't covered by the pact that only limits strategic nuclear arsenals. Moscow says it can't accept the demand.

Speaking at a meeting of his Security Council, Putin said that "it would be extremely sad if the treaty ceases to exist without being replaced by another fundamental document of the kind."

"All those years, the New START has worked, playing its fundamental role of limiting and containing an arms race," he noted.

The New START treaty was signed in 2010 by U.S. President Barack Obama and Russian President Dmitry Medvedev. The pact limits each country to no more than 1,550 deployed nuclear warheads and 700 deployed missiles and bombers, and envisages sweeping on-site inspections to verify compliance.

After both Moscow and Washington withdrew from the 1987 Intermediate-range Nuclear Forces Treaty last year, New START is the only nuclear arms control deal between the two countries still standing.

Putin on Friday proposed to "extend the existing treaty without any conditions for at least one year" to allow for "substantive talks," instructing Russian Foreign Minister Sergey Lavrov to get a quick U.S. answer to the offer. He emphasized that Russia is ready to discuss the new weapons it has deployed in future arms talks with the United States.

Russia previously offered the pact's extension for five years without any conditions, while the U.S. administration pushed for a new arms control agreement that would also include China. Moscow has described that idea as unfeasible, pointing at Beijing's refusal to negotiate any deal that would reduce its much-smaller nuclear arsenal.

President Donald Trump's national security adviser Robert O'Brien said Friday that, with Beijing stonewalling offers to join the talks, Washington is now ready to strike a deal with Russia.

"The Chinese are so busy building nuclear warheads and building their military that they're not interested," he said during a webinar hosted by the Aspen Institute, adding that the U.S. is "prepared to go forward with a U.S.-Russia arms control deal."

But Lavrov voiced skepticism about reaching a deal on New START, noting that Russia can't accept the conditions put forward by the United States for its extension.

He specified that Russia can't agree to the U.S. proposal to limit battlefield nuclear weapons alongside nuclear warheads that arm strategic missiles and bombers until the U.S. agrees to withdraw its tactical nuclear weapons from Europe.

The top Russian diplomat also noted that Moscow wouldn't accept the U.S. demand to have intrusive verification measures like those that existed in the 1990s when inspectors were positioned at missile factories.

O'Brien said the U.S. has made "a relatively straightforward proposal that we extend New START for a year and that the Russians cap their nuclear warhead number for a year," but added that "negotiating with Russia is never easy."

O'Brien also observed that "it may be that, like other countries, the Russians are waiting to see what happens" in the Nov. 3 U.S. election.

He added: "It very well may be that the Russians don't respond and continue to build warheads and refuse to short term freeze and we'll take that into account."

"We thought we made a really fair, terrific proposal that would have given the parties another year or so to negotiate an overall big deal, and we'll see if the Russians take it or not," O'Brien said.

After the last round of talks in Helsinki earlier this month, lead U.S. negotiator Marshall Billingslea, Trump's special envoy for arms control, said the meeting had yielded "important progress."

But his Russian counterpart in the talks, Deputy Foreign Minister Sergei Ryabkov, dismissed the allegations of reaching the agreement in principle as "wishful thinking" on the U.S. part, emphasizing that sharp differences remained and Moscow wasn't going to sign a deal on the U.S. terms.

In Washington, Daryl Kimball, executive director of the Arms Control Association, said in an interview that he hopes Trump accepts Putin's offer of a short-term treaty extension without conditions, given the approaching expiration of New START in early February.

"We're in the 11th hour now, and we'd urge President Trump to take yes for an answer," Kimball said, adding that he believes this would draw broad bipartisan support in the U.S.

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Associated Press writers Robert Burns and Deb Riechmann contributed to this report from Washington.