WASHINGTON, Dec. 1 -- US President Donald Trump has had "informal" conversation with his Russian counterpart Vladimir Putin on Friday, said the White House on Saturday.

According to a statement issued by the White House spokesperson Sarah Sanders, "as is typical at multilateral events, President Trump and the First Lady had a number of informal conversations with world leaders at the dinner last night, including President Putin."

However, she did not elaborate the content of the conversation.

Trump tweeted earlier on Thursday before arriving in Argentina for the Group of 20 summit that "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... in Argentina with President Vladimir Putin."

"I look forward to a meaningful Summit again as soon as this situation is resolved!" he added.

In his interview with CNN on Saturday, US Secretary of State Mike Pompeo explained that Trump had canceled the meeting "because the Russians behaved in a way that is deeply inconsistent with international law and is outrageous."

"The President wanted to send a clear, unambiguous message that we find that type of behavior unacceptable, and so he canceled the meeting... he wanted to send an unambiguous message that the Russians needed to change that act," he said. "President Trump made the decision this was the right approach based on the activity that had taken place in the lead-up to the G20 summit."

Speaking about the conditions for a second Trump-Putin summit, Pompeo said that "we want the sailors returned, we want the ships returned."

"Now this jumped in the middle of a time when they could have begun to have a discussion where we might have made some progress," he noted. "We regret that, but the Russians caused this meeting to be canceled by their behavior in the Kerch Strait."

The Ukrainian Navy said Sunday that Russian forces opened fire and seized three Ukrainian ships near the Kerch Strait, adding that six Ukrainian military sailors were wounded, two of them in serious condition.

Russian authorities said the Ukrainian ships breached the Russian border and conducted dangerous maneuvers in spite of orders of accompanying Russian vessels.

The Ukrainian Navy said that it had informed Russia in advance about the passage of Ukrainian vessels from the Black Sea to the Sea of Azov through the Kerch Strait.

The Ukrainian parliament supported a bill earlier this week imposing a martial law in certain regions for 30 days starting from Wednesday due to the tensions with Russia in the Sea of Azov.