The UK government has said rules allowing EU nationals to live and work freely in the UK will end in the event of a no-deal Brexit on 31 October, according to a BBC report.
Theresa May had considered extending freedom of movement to 2021 or allowing EU citizens to stay for three months before applying for a longer stay.
Those options have now been dropped, in favour of a new approach to be set out later.
Boris Johnson said the UK would not “become hostile to immigration”.
The PM added that “immigration into the UK will be democratically controlled”.
The Three Million group, which campaigns for the rights of EU citizens living in the UK said: “Ending freedom of movement without putting legal provisions in place for those EU citizens who have not yet successfully applied through the settlement scheme will mean that millions of lawful citizens will have their legal status removed overnight.”
Freedom of movement allows EU citizens to live and work in other European Union countries.
In a statement, the Home Office said: “EU citizens and their families still have until at least December 2020 to apply to the EU Settlement Scheme and one million people have already been granted status.
“Freedom of movement as it currently stands will end on 31 October when the UK leaves the EU, and after Brexit the government will introduce a new, fairer immigration system that prioritises skills and what people can contribute to the UK, rather than where they come from.”
A Downing Street spokeswoman added that “tougher criminality rules” for those coming to the UK will be introduced.