Boris Johnson has said the UK will eventually welcome hundreds of thousands of Ukrainian refugees, but said it would be “irresponsible” to “simply to wave people through”.
The government is under pressure from all sides, including many Tory MPs, over the number of refugees it has let in compared to other European countries.
So far just 760 UK visas have been granted to Ukrainians since Vladimir Putin launched his invasion two weeks ago.
Speaking during PMQs on Wednesday, the prime minister said this number would rise “very sharply”.
“We expect those numbers to rise in the region of the hundreds of thousands,” he said.
Johnson told MPs that Michael Gove, the levelling up secretary, would soon set out new routes by which Ukrainians can come to the UK.
But the PM rejected demands that all Ukrainians be welcomed without the need for security checks.
“It would not be right to expose this country to unnecessary risk and we will not do it,” he said.
He said to “simply to wave people through” the border would be “irresponsible”.
SNP Westminster leader Ian Blackford said the government’s handling of refugees so far had been “disgraceful”.
He said Ireland had managed to give sanctuary to “three times as many refugees” as the UK.
“These numbers don’t lie, they tell a devastating truth. Does the prime minister find it acceptable that his home secretary has overseen one of the slowest, most bureaucratic and incompetent refugee responses in the whole of Europe?” he said.
The United Nations has estimated at least two million people have left Ukraine to escape the war.