Labour would refuse to back any action in Syria unless it had the support of Russia, the Labour leader said, following the go ahead granted by Mrs May to the cruise missile attacks on Syria in a joint operation with the United States and France.
Foreign Secretary Boris Johnson said “finally the world has said enough is enough” as he defended the “proportionate” action, but Mr Corbyn wants a War Powers Act that would stop governments launching military offensives in most circumstances without MPs’ consent.
Russia has repeatedly used its UN veto to block sanctions and investigations during the civil war in Syria.
Asked if there were any circumstances in which he would back air strikes in Syria, Mr Corbyn said: “I can only countenance involvement in Syria if there is a UN authority behind it.
“If we could get to a process in the UN where you get to a ceasefire, you get to a political solution, you then may well get to a situation where there could be a UN force established to enforce that ceasefire.”
Scotland’s First Minister Nicola Sturgeon said it was a “serious mistake” for the role of UK armed forces in Syria to be altered without Parliament’s approval, while shadow foreign secretary Emily Thornberry said taking military action against Bashar Assad’s regime was the “wrong thing to do”.
“We think that it should be in law that there should be a vote in Parliament before we take military action,” she said.
“Not urgent cases. Clearly not when we are under attack or the Prime Minister has been kidnapped, or anything like that.”
But David Lidington, the Prime Minister’s deputy, said there were “no plans” for legislation.
The Cabinet minister said he was “not going to rule anything in or rule anything out” about whether the Government would give MPs a vote if fresh action was taken in Syria.
Foreign Secretary Mr Johnson said: “There is no proposal on the table at the moment for further attacks because so far - thank heavens - the Assad regime has not been so foolish to launch another chemical weapons attack.
“If and when such a thing were to happen then clearly, with allies, we would study what the options were,” he added.
Mrs May insisted the decision to deploy British cruise missiles in response to the chemical attack in Douma was “both right and legal”, while Nato allies had given the action their full support, its secretary general Jens Stoltenberg said.
Syria’s President Bashar Assad said the air strikes against his country were accompanied by a campaign of “lies and misinformation” at the UN. Assad and Russia deny using chemical weapons, the trigger for the strikes early on Saturday.
Seven years of Syrian conflict led to an alleged gas attack last weekend in the town of Douma killed more than 40 people, opposition activists and rescuers have reported.