Geopolitical fault lines were on display at the United Nations on Monday, as Western countries decried the seizure of Ukrainian ships by Russian forces, while China joined others in backing Moscow’s agenda for an emergency session of the Security Council.

On Sunday, Russia fired on and seized three Ukrainian naval vessels, also detaining the 23 sailors on board, prompting calls for the emergency meeting at the UN Monday morning. The incident occurred as the ships were sailing through the Kerch Strait, located off the coast of Crimea, which was annexed by Russia in 2014 but is not yet widely recognized as Russian territory.

Footage of the incident released by the Russian military was uploaded to YouTube:

Western media outlets cited diplomatic sources as saying that the meeting had been called by both Russia and Ukraine, a claim disputed by Moscow.

“Yesterday, after Russia had requested this Security Council session to be held, our Western partners tried to present it as if it was Ukraine, not Russia, who had requested it. Gentlemen, this is just petty. As measly as it gets,” Russian envoy to the UN Dmitry Polyansky was quoted by Tass as saying.

Seven Security Council members voted down a meeting agenda proposed by Moscow, while China, Russia, Kazakhstan and Bolivia voted in favor of it.

US Ambassador to the UN Nikki Haley issued a statement on behalf of the Trump administration, decrying what she called an “outrageous violation of sovereign Ukrainian territory.”

While the White House issued no statement on the seizure, Haley said her comments reflected concerns at the “highest level” of the government, following consultation with the president and secretary of state.

Ukrainian President Petro Poroshenko demanded that Russia immediately release the ships and sailors, a move which Moscow gave no indication it was prepared to carry out, per Radio Free Europe. Kremlin spokesman Dmitry Peskov said that the sailors would be held responsible under Russian law for violating the border.

European Council President Donald Tusk backed Poroshenko’s calls for the release of the sailors via Twitter.

Poroshenko, meanwhile, has declared martial law in Ukraine, a decision that requires approval by the parliament. He announced the move in a statement posted online, saying that Parliament will consider the decision in a special session on Monday.

As of 8:30 PM local Ukraine time on Monday, the parliament was still debating the details of a possible imposition of martial law, according to a Tweet from Christopher Miller of Radio Free Europe: