London's mayor Ken Livingstone said on Tuesday it was a mistake to allow Chinese secret police officers to guard the Olympic torch when it was paraded through London earlier this month.
"It was wrong and should not have happened," Livingstone told a BBC Radio London debate.
Livingstone, who is standing for re-election as Labour's candidate in London's mayoral elections next month, was taking part in the debate with two of his fellow candidates, Boris Johnson of the Conservatives and Brian Paddick, representing the Liberal Democrats.
The debate was being broadcast later on Tuesday but his remarks were carried earlier on the BBC's website ().
Livingstone was asked if he knew in advance that the Olympic torch guards were members of China's military secret police and he said he did not.
"Had I known, I would have said it was unacceptable," he said.
"We are not involved in the running of the Olympics during the election campaign."
Metropolitan police officers later criticized the guards, distinguished in their bright blue tracksuits, after scuffles broke out between police and anti-China protesters.
Sebastian Coe, the head of London's 2012 Olympics Organising Committee, described the guards as "thugs" who, he claimed, tried to push him out of the way of the procession.