British Labour Party leader Jeremy Corbyn stood firmly against other European leaders on Tuesday as many appeared ready to follow President Donald Trump into battle, after Trump made overtures regarding a possible attack on Syria.

Corbyn condemned the suspected use of a chemical weapon in the town of Douma, which killed at least 42 civilians over the weekend—and urged a political solution to the ongoing civil war in Syria, strongly cautioning against military action by the U.K., the U.S., or other Western allies.

“The tragedy and the terror of people’s lives in Syria can only end by a political solution,” Corbyn said Tuesday. “That means every country in the region—every country in the region, as well as Russia and the United States—coming together to ensure there is a meaningful ceasefire and there is a political process.”

While Trump warned that the U.S. has “a lot of options militarily,” Corbyn said the international community must first and foremost investigate the attack on Douma.

“I call on all parties to cooperate urgently with the UN in conducting an inquiry into this so we can find out exactly who delivered that chemical weapon,” Corbyn said. “The evidence is important and the use of international law is crucial to bring about a more peaceful world in the future.”

Other European leaders have appeared all-to-eager to wage an attack on Syria in the wake of the weekend’s violence. British Foreign Secretary Boris Johnson echoed Trump’s comments by saying, “a full range of options should be on the table,” while French Prime Minister Édouard Philippe called for a “strong, united and resolute” international response to the chemical attack and told parliament, “our reaction to the use of these weapons will say things about who we are.”