Home Secretary Priti Patel has suggested Labour MPs cannot be trusted with security briefings which highlight threats to the UK amid the Ukraine crisis.
Ms Patel claimed she could not waive all visa rules for people fleeing Ukraine because of the "strongest security advice".
But when making a statement in the Commons on Tuesday, she could not explain what those security issues were.
Stressing the "seriousness of the security" situation, Ms Patel said: "Russian troops are seeking to infiltrate and merge with Ukranian forces. Extremists are on the ground in the region too."
She added: "I am sure that if the Opposition want a security briefing from our colleagues, we will happily provide one, but I am very sceptical about how they treat and respect security advice."
Former minister and Labour MP Angela Eagle hit out after the remarks, as Ms Patel had failed to explain why the security concerns meant she could not welcome more refugees to the UK.
Former Labour home secretary Jacqui Smith tweeted: "That’s an unwarranted slur on the current opposition and unworthy of a home secretary.”
Ms Patel told MPs Russian troops are "seeking to infiltrate and merge with Ukrainian forces” and there are “extremists on the ground” in Ukraine.
The Home Secretary added: “Given this and also Putin’s willingness to do violence on British soil, and in keeping with our approach which we have retained consistently throughout all emergency evacuations including in Afghanistan, we cannot suspend any security or biometric checks on people we welcome to our country.
“We have collective duty to keep the British people safe and this approach is based on the strongest security advice.”
Ms Patel's remarks come despite being sacked from Theresa May's government for holding off the book meetings with the Israeli government.
