AP

LONDON (AP) — Britain's House of Commons on Monday rejected an attempt to make the government promise, before the start of European Union exit talks, that it will guarantee the right of EU citizens living in the U.K. to remain.

By a vote of 335 to 287, lawmakers overturned an amendment to the government's Brexit bill inserted by the unelected House of Lords.

They also rejected, by 331 to 286, a demand that Parliament get a "meaningful" vote on the final deal between Britain and the other 27 nations of the bloc.

Members of the House of Lords now have to decide whether to accept the Commons vote or resist, delaying the bill's passage. If they back down, the bill could be approved by late Monday.

That would leave Prime Minister Theresa May free to invoke Article 50 of the EU's key treaty — the trigger for two years of exit negotiations — by March 31, as planned.

May needs Parliament's approval before she can start the talks. The House of Commons and House of Lords have been battling over the bill's contents.

Brexit Secretary David Davis urged Parliament to approve the bill without amendment or delay, "so the prime minister can get to work on the negotiations."

Davis said the government had a "moral responsibility" to the 3 million EU citizens living in Britain and the 1 million Britons in other member states, and intends to guarantee their rights as soon as possible after exit talks start.

"That is why we must pass this straightforward bill without further delay so the prime minister can get to work on the negotiations and we can secure a quick deal that secures the status of both European Union citizens in the U.K. and also U.K. nationals living in the EU," he said.

Pro-EU lawmakers accused the government of running roughshod over the concerns of the 48 percent of Britons who voted to stay in the EU by rejecting the Lords amendments.

Conservative legislator Dominic Grieve called the government's opposition of handing Parliament a final vote on Brexit "deranged," and the Green Party's Caroline Lucas said lawmakers should not just hand ministers a blank check.

"We were not elected to be lemmings," she said.

Euroskeptics accused pro-EU legislators of trying to frustrate the will of voters, who decided in a June referendum to leave the EU.

"The simple truth is this — deal or no deal, vote or no vote, positive vote or negative vote, this process is irreversible," said Conservative legislator Edward Leigh. "We're leaving the EU and that's what the people want."

Once the bill is passed by both houses of Parliament, the bill becomes law once it has received royal approval — a quick formality.

Amid speculation she could trigger Article 50 as early as Tuesday, May spokesman James Slack repeated the government's position that it would happen by the end of March.

"I've said 'end' many times but it would seem I didn't put it in capital letters strongly enough," he said.

The government says voters have spoken and Britons should unite behind the decision to leave. But May's government got a shock rebuff Monday from Scottish First Minister Nicola Sturgeon, who announced she would seek authority to hold an independence referendum in the next two years because Britain is dragging Scotland out of the EU against its will.

While Britons overall voted to leave the EU, Scottish voters backed remaining by 62 to 38 percent.

Sturgeon said she would seek to hold a referendum between the fall of 2018 and the spring of 2019 so that Scotland won't be "taken down a path that we do not want to go down without a choice."

In a 2014 referendum, Scottish voters rejected independence by a margin of 55 percent to 45 percent. But Sturgeon said that the U.K.'s decision to leave the EU had brought about a "material change of circumstances."