"I tend to think of as credible comments by the bishop of Tripoli monsignor Martinelli who told us that Gaddafi is very probably outside of Tripoli and probably also injured. But we don't know where he is," Italian Foreign Minister Franco Frattini told reporters.

He earlier told Corriere della Sera daily in an interview: "I am of the view that he has probably fled from Tripoli but not from the country."

Frattini also cast doubt on the reliability of television images showing Gaddafi on state television earlier this week.

"I have a lot of doubts that those images were shot that day," he said.

Frattini said international pressure was causing "the disintegration of the regime from the inside, which is what we wanted," adding that arms depots had been raided by rebels in the outskirts of the capital in the last few hours.

"We have seen some rebel flags flying... in eastern Tripoli," he said.

"International pressure has apparently provoked a decision by Gaddafi to seek refuge in a safer place," Frattini said.

He said one of Gaddafi's nephews had called on the Gaddafa tribe not to support the colonel any longer at an opposition meeting in Doha this week.

He also accused Gaddafi's regime of deliberately sending boats crammed with refugees towards Italy, saying this was "a criminal instrument" that should be taken up by prosecutors from the International Criminal Court (ICC).

Asked about when the conflict could end, he answered: "I don't think there is long left... The key moment will be formal charges against Gaddafi at the International Criminal Court in a few weeks and presumably by the end of May."

ICC prosecutor Luis Moreno-Ocampo also on Friday said he would seek arrest warrants on Monday for three people considered most responsible for crimes against humanity in Libya, one of whom is believed to be Gaddafi.

Judges at the court, based in The Hague in the Netherlands, can then decide whether to accept the application, reject it or ask for additional information.