MPs have criticised the government for not guaranteeing the rights of EU citizens to remain in the UK after the country leaves the European Union.
Ministers say it would be “unwise” to fully “guarantee” EU citizens’ rights without a deal for Britons abroad.
Foreign Secretary Philip Hammond told the BBC a deal that “works both ways” had to be negotiated in Brexit talks.
But MPs from all parties have attacked the government’s stance, saying people “are not bargaining chips”.
It comes after Home Secretary Theresa May – who is a candidate in the Conservative Party leadership contest – said on Sunday she wanted to “guarantee the position” for EU citizens living in the UK and British citizens living in EU countries – but that it would be a factor in Brexit negotiations.
The government has said there will be “no immediate change” to the status of EU citizens living in the UK pending Brexit negotiations.
In a BBC interview, Foreign Secretary Philip Hammond – who is backing Mrs May to be the next leader and prime minister – said he thought it “most unlikely” that EU nationals already living in the UK would be told they could not stay, and called for informal talks before the UK officially triggers its departure from the EU.
But he said to fully guarantee EU citizens’ rights to remain in the UK, without commitments from other countries towards Britons abroad, now risked “selling our people out too cheap”.
“You can’t say anything until we have had the negotiation because clearly this has to be a bilateral agreement.
“There has to be some symmetry between the treatment of UK nationals in EU countries and EU nationals in UK countries,” he told BBC political editor Laura Kuenssberg.
He said he hoped a deal could be struck with other EU countries so they and Britons can “carry on exactly as before”.
The government’s stance was criticised by MPs – including from the government’s own side – during an urgent question in the House of Commons.
Anne Main, Tory MP and Brexit backer, said: “Nobody on the official Leave campaign raised the prospect of sending people away and deporting people.
“This has been raised by the home secretary and it is a catastrophic error of judgment for someone who wishes to lead this country to even suggest those people who are here legally, working with families and settled, should be even part of the negotiations.”
Labour MP and Brexit campaigner Gisela Stuart – who tabled the Commons question – said the UK should not “retrospectively change the rights of its citizens”, and that anything other than a guarantee was “a failure of this government to protect its people”.
She said EU nationals “are not bargaining chips” – an argument that has separately been made by Tory leadership contender Andrea Leadsom.
Immigration minister James Brokenshire defended the government’s position, saying there would be “no immediate change” affecting EU citizens, but that whether to offer an absolute guarantee would be a decision for the next prime minister.
“I am not in a position to make new policy announcements this afternoon,” he added.
SNP home affairs spokeswoman Joanna Cherry criticised the home secretary for not responding to the urgent question herself.
Mrs May has said she wants to “guarantee the position” of EU nationals but that their status would form part of the forthcoming Brexit negotiations.
Labour’s shadow home secretary Andy Burnham said her “threatening” comments about the uncertain status of EU nationals following the vote to leave undermined family life in the UK, including his own.
Mr Burnham, who has three children with his Dutch wife, said: “Any uncertainty hanging over their right to be here is tantamount to undermining family life in our country and that does not strike me as a very prime ministerial thing to do.”
Mrs May’s rival leadership contenders Mrs Leadsom and Michael Gove have both said EU nationals should be allowed to stay in the UK.