President-elect Donald Trump called on Sunday for an immediate ceasefire in Ukraine, saying after meeting with world leaders in Paris that Ukraine and its president “would like to make a deal and stop the madness.”

“There should be an immediate ceasefire and negotiations should begin,” Trump wrote in a post on social media, calling the war between Russia and Ukraine one that “should never have started, and could go on forever.”

Trump was in Paris on Saturday to attend the reopening of the Notre Dame Cathedral and met with world leaders including Ukrainian President Volodymyr Zelenskyy and French President Emmanuel Macron. The meeting marked Trump’s first in-person conversation with the Ukrainian president since he won the presidential election in November. 

The president-elect has repeatedly pledged that he would end the war between Russia and Ukraine immediately upon returning to the White House while claiming that Russian President Vladimir Putin would never have invaded the country if he were president. 

Trump, who has provided few details about how he would bring a negotiated end to the war, said in the post on Sunday that “I know Vladimir well,” adding that it’s “his time to act.”

Zelenskyy said Sunday that he had a “good meeting” with Trump, outlining that he told the president-elect that Ukraine needs “a just and enduring peace” that “Russians will not be able to destroy in a few years, as they have done repeatedly in the past.”

The Ukrainian president said in a post on social media that the war “cannot simply end with a piece of paper and a few signatures,” urging that a ceasefire “without guarantees can be reignited at any moment.” Zelenskyy argued that Putin “can only be stopped by strength — the strength of world leaders who can become leaders of peace. “

“We count on America and the entire world to help stop Putin,” Zelenskyy said. “The only things he fears are America and global unity.”

The U.S. on Saturday announced a new $988 million military assistance package for Ukraine. The package features drones, ammunition for precision HIMARS rocket launchers, and equipment and spare parts for artillery systems, tanks and armored vehicles, the Pentagon said in a statement.