WASHINGTON (AP) — Donald Trump on Sunday pushed Russian leader Vladimir Putin to act to reach an immediate ceasefire with Ukraine, describing it as part of his active efforts as president-elect to end the war despite being weeks from taking office.

“Zelensky and Ukraine would like to make a deal and stop the madness,” Trump wrote on social media, referring to Ukraine’s president, Volodymyr Zelenskyy.

In a television interview that aired Sunday, Trump also said he would be open to reducing military aid to Ukraine and pulling the United States out of NATO. Those are two threats that have alarmed Ukraine, NATO allies and many in the U.S. national security community.

Asked on NBC’s “Meet the Press” if he were actively working to end the nearly 3-year-old Ukraine war, Trump said, “I am.”

He refused to say if he had spoken to Putin since winning the election in November. “I don’t want to say anything about that, because I don’t want to do anything that could impede the negotiation,” Trump said.

Trump’s call for an immediate ceasefire went beyond the public policy stands taken by both the Biden administration and Ukraine and drew a cautious response from Zelenskyy. It also marks Trump’s wading unusually deeply into efforts before his inauguration on Jan. 20 to resolve one of the major global crises facing the lame-duck Biden administration.

Trump made his proposal after a weekend meeting in Paris with French and Ukrainian leaders in Paris, where many world leaders gathered to celebrate the restoration of Notre Dame cathedral after a devastating fire. None of the advisers traveling with him appeared to have expertise on Ukraine.

Kyiv would like to close a deal, Trump wrote on his social media platform Truth Social. “There should be an immediate ceasefire and negotiations should begin.”

“I know Vladimir well. This is his time to act. China can help. The World is waiting!” Trump added. He was referring to mediation efforts by China that many in the West have seen as favoring Russia.

Zelenskyy described his discussions Saturday with Trump, brought together by French President Emmanuel Macron, as “constructive” but has given no further details.

In a post Sunday on the Telegram messaging app, Zelenskyy cautioned that Ukraine needs a “just and robust peace, that Russians will not destroy within a few years.”

“When we talk about an effective peace with Russia, we must talk first of all about effective peace guarantees. Ukrainians want peace more than anyone else. Russia brought war to our land,” Zelenskyy said.

Kremlin spokesman Dmitry Peskov responded to Trump’s post by repeating Moscow’s longstanding message that it is open to talks with Ukraine. Peskov referenced a decree by Zelenskyy from October 2022 that formally declared the prospect of any talks “impossible” as long as Putin was Russia’s leader.

That decree came after Putin proclaimed four occupied regions of Ukraine to be part of Russia, in what Kyiv and the West said was a clear violation of Ukrainian sovereignty.

Trump’s former national security adviser, retired Lt. Gen. H.R. McMaster, warned there was no such thing as a quick fix to ending Russia’s war with Ukraine.

“What I’m worried about is this kind of flawed idea that Putin can be placated, right, that Putin will come to some kind of a deal,” McMaster told “Fox News Sunday.”

“I think it’s really important for President Trump to adhere to his instinct in this connection ... peace through strength,” McMaster said, adding, “How about give them what they need to defend themselves, and then saying to Putin, ‘You’re going to lose this war?”’

While Trump has said before that he would like to see a quick ceasefire in Ukraine, his proposal Sunday was framed as a direct appeal to Russia. The quick responses from Ukraine and Russia demonstrated the seriousness with which they regarded the idea from the incoming American president.

Both Trump and Biden administration officials have pointed to Russia’s disengagement in Syria, where the Russian military largely moved out of the way in recent days as Syrian rebels overthrew the country’s Russian-allied president, as evidence of the extent to which the Ukraine war has sapped Russia’s resources.

The Biden administration and other supporters of Ukraine have made a point of not being seen to press Ukraine for an immediate truce. Ukraine’s allies fear a quick deal would be largely on the terms of its more powerful neighbor, potentially forcing damaging concessions on Ukraine and allowing Russia to resume the war again once it has built back up its military strength.

For most of the war, Kyiv’s official position has been to call for a full withdrawal of Russian troops from internationally recognized Ukrainian territory, including Crimea, as a condition for peace talks. Moscow, too, has demanded heavy concessions from Ukraine as a condition for even beginning talks.

Trump portrays himself as up to making fast deals to resolve conflicts in Ukraine and the Middle East that have frustrated many of the Biden administration’s own mediation efforts.

There is no prohibition on incoming officials or nominees meeting with foreign officials, and it is common and fine for them to do so — unless those meetings are designed to subvert or otherwise affect current U.S. policy.

The Logan Act bars private citizens from trying to intervene in “disputes or controversies” between the United States and foreign powers without government approval. But the 1799 statute has produced just two criminal cases, none since the 1850s and neither resulting in a criminal conviction.

In the NBC interview that was taped Friday, Trump renewed his warning to NATO allies that he did not see continued U.S. participation in the Western military alliance as a given during his second term.

Trump has long complained that European and the Canadian governments in the mutual-defense bloc are freeloading on military spending by the U.S., by far the most powerful partner in NATO. NATO and its member governments say a majority of countries in the bloc are now hitting voluntary targets for military spending, due in part to pressure from Trump in his first term.

Asked whether he would consider the possibility of pulling out of NATO, Trump indicated that was an open question.

“If they’re paying their bills, and if I think they’re treating us fairly, the answer is absolutely I’d stay with NATO,” he said.

But if not, he was asked if he would consider pulling the U.S. out of the alliance. Trump responded, “Absolutely. Yeah, absolutely.”

Trump expressed the same openness when asked if Ukraine should brace for possible cuts in U.S. aid. “Possibly,” he said.

U.S. arms and other military support are vital to Ukraine’s efforts to fend off invading Russian forces, and Democratic President Joe Biden has been surging assistance to Ukraine ahead of leaving office.

Defense Secretary Lloyd Austin on Saturday announced nearly $1 billion more in longer-term weapons support to Ukraine. Austin spoke to his Ukrainian counterpart, Rustem Umerov, on Sunday about the status of the war and U.S. military backing, the Pentagon said.