"Stronger checks" will be carried out to stop foreign criminals from becoming UK citizens if Labour wins the next election, Yvette Cooper has said.
The shadow home secretary told the BBC it was "shocking" that killers had been given British passports because "the Home Office failed to do basic checks".
The Home Office said it had inherited an immigration system "in disarray" and had introduced widespread reforms.
Chief borders inspector John Vine criticised existing checks, last week.
He said the Home Office had granted British citizenship to people with "very poor immigration histories" and he had been "concerned" to discover that applications for UK citizenship were not being scrutinised appropriately.
Ms Cooper told BBC One's Andrew Marr Show: "I think it's shocking that we have had people including serious criminals and killers [being] given British passports and British citizenship because the Home Office failed to do basic checks.
"I think we need much stronger checks in place, that must include a requirement on people applying for British citizenship to provide the equivalent of the Criminal Records Bureau checks from their own country."
Checks would be made on those without such a document to see if they have a criminal record in their own country.
She added that there would be more thorough border checks, aided by the proposed 1,000 additional border staff funded by visa waiver charges.
"We don't want those who have committed serious crimes abroad able to take advantage of British citizenship. We should have fair rules in place. Immigration is important to Britain but the system has got to be fair."
Ms Cooper said immigration had been "too high" because of the level of low-skilled migration, which Labour would like to see lower - but she said they would not be promising a "no ifs, no buts" target, like the government's, which had been left in "tatters".
Student visitor visas, for short-term temporary students, and recruitment agencies that only recruited abroad and were undercutting local wages were areas that should be tackled.
Which begs the question: Why didn't they do it when they were in power?
