Five foreign criminals released from prison in recent years without being considered for deportation have since been arrested and convicted of drug-related or violent crimes, Britain's top law enforcement official said Friday.

The government's failure to properly consider deportation for 1,023 prisoners before freeing them over the past seven years has created a public uproar and political headache for Prime Minister Tony Blair since Home Secretary Charles Clarke revealed it earlier this week.

The home secretary said a search of police records found that five of the prisoners had been convicted of offenses involving drugs or violence since their release.

His office said it would not reveal precise details of the new offenses.

A rape allegation was made against one prisoner but there was insufficient evidence to prosecute, Clarke said. A separate allegation of rape against another is currently being investigated, he said.

Clarke said the search had revealed no other cases in which an offender was convicted of a serious crime, although some of the released foreign criminals are being investigated on minor charges.

Some had speculated that news of serious new crimes by the convicts could mean the end of Clarke's political career but the prime minister's official spokesman said Friday that Blair maintained "full confidence" in Clarke. The home secretary said he would report again next week on efforts to track all the freed prisoners, an indication he did not intend to quit, as opponents have demanded.

The controversy is part of a string of political embarrassments that could weaken Blair before local elections next week.

A poll showed 63 percent of Britons thought Clarke should be fired. The Populus polling firm questioned 1,004 people on Wednesday and Thursday for the survey, which had a margin of error of 3 percentage points.

The home secretary has apologized repeatedly for his department's failings, and did so again Friday.

"I very much regret the shortcomings which I've reported," he said. "The home office is in the process of dramatic change to enable us to meet the challenges of the modern world effectively."

Opposition Conservative party lawmaker David Davis called on Clarke to resign and said the minister's "position is untenable."

"He should take responsibility for what has been a massive failure," Davis said.

Clarke disclosed Tuesday that the 1,023 foreign criminals who should have been considered for deportation had instead completed their sentences in British prisons and gone free between February 1999 and March 2006.

He initially said "very few" such prisoners had been released without being considered for deportation after the problem came to his attention last year, but later confirmed that the number was 288, more than a fourth of the total.

Clarke said Friday that officials had examined the cases of 72 of the 79 freed criminals convicted of the most serious offenses and were moving to deport 63. He did not say what he meant by the most serious offenses, or why the government was only trying to deport 63.

Six of the 63 prisoners have been detained, and officials expect more arrests over the weekend, he said.