Donald Trump on Thursday called off his upcoming scheduled meeting with Russian President Vladimir Putin, citing the ongoing naval standoff between Russia and Ukraine. “Based on the fact that the ships and sailors have not been returned to Ukraine from Russia, I have decided it would be best for all parties concerned to cancel my previously scheduled meeting,” Trump tweeted. The meeting had been scheduled to take place this Saturday on the sidelines of the G-20 summit in Argentina.

Shortly afterward, the AP reported that Trump would also be calling off sit-down meetings with President Recep Tayyip Erdogan of Turkey and President Moon Jae-in of South Korea. His talks with those leaders have been reduced to informal “pull-asides” on the sidelines of the summit.

In addition to the Ukraine crisis, the Putin-Trump meeting would have taken place against the backdrop of new revelations from special counsel Robert Mueller’s investigation into Russia’s role in the 2016 election, and a plea deal for Trump’s former lawyer Michael Cohen for lying to Congress about Trump’s business interests in Russia.

This marks the second major gathering in a row, after the commemoration of the World War I armistice in Paris earlier this month, that both Putin and Trump attended without having a formal sit-down. (Trump did greet Putin warmly at the ceremony, and they attended a lunch together with the other leaders.) Their latest formal meeting was the high-profile summit in Helsinki in July. The Kremlin responded snippily to Thursday’s announcement, saying that Putin would now have more time for “useful meetings.”

Trump had initially declined to respond for more than a day after the incident last weekend in which Russian ships opened fire and seized three Ukrainian vessels near the Kerch Strait between Crimea and the Russian mainland. When he did weigh in, he declined to blame Russia, saying, “We do not like what’s happening either way. And hopefully it will get straightened out,” despite the fact that his own U.N. ambassador, Nikki Haley, had earlier condemned Russia for what she called an “outrageous violation of sovereign Ukrainian territory.” On Wednesday, Trump appears to have shifted his position on Russia’s actions, saying, “I don’t like that aggression” in an interview with the Washington Post and suggesting he might cancel the Putin meeting.

The latest crisis shows little sign of abating. A court in Russian-annexed Crimea on Wednesday ordered the captured sailors to be detained for two months, pending a possible trial for what Russia says was an illegal crossing of its borders. Ukrainian President Petro Poroshenko has called for Western countries to apply additional sanctions on Russia over its actions and for NATO to deploy more warships to the area. But tougher actions from Europe or the U.S. appear unlikely for the moment, despite widespread condemnation of Russia’s actions.

The additional cancellations of meetings with the leaders of Turkey and South Korea seems like an attempt to downplay the significance of the Russia announcement. It will also allow Trump to avoid what would be awkward conversations about his staunch backing of Saudi Arabia and the uneasy state of nuclear diplomacy with North Korea. Trump has also made a habit of skipping events and taking off early on previous foreign trips, so his staff may just have wanted to keep his schedule light.

Trump is still expected to sit down with President Xi Jinping of China for a highly anticipated meeting amid an escalating trade war between the two superpowers. And Putin will meet with Saudi Arabian Crown Prince Mohammed bin Salman, who may find himself something of a pariah at the gathering over his alleged role in the killing of journalist Jamal Khashoggi. The two oil-rich autocrats, both favorites of Trump’s who have likely found relations with the U.S. more complicated than anticipated lately, should have a lot to talk about.