President Donald Trump said on social media Saturday that a deal better than “a mere Ceasefire” is in the works with Vladimir Putin, hours after Trump’s high-stakes summit with the Russian leader in Alaska failed to produce an agreement to halt Russia’s invasion of Ukraine.

Trump spoke directly with Zelenskyy and European leaders early Saturday about the U.S. potentially joining a NATO-style security guarantee for Ukraine as part of a deal with Russia, according to two senior administration officials and three sources familiar with the discussions.