David Cameron has praised the bravery of UK military forces in action over Libya and insisted the campaign will continue until civilians are "safe and secure from attack".
The Prime Minister said the coalition had been right to act "quickly and decisively", but the situation remained "grave" in Misurata and Zintan.
British forces had now carried out 70 sorties against Muammar Gaddafi's troops, including striking at tanks on the ground, he said.
"I want to thank all of those involved for their incredible skill and bravery," Mr Cameron told journalists in Brussels. "The situation of civilians in Misrata and Zintan is grave. But we have moved quickly and decisively over the last week and I think it was right to do so."
Mr Cameron said the EU summit had agreed that "military action should continue until people are safe and secure and until UN Security Council Resolution 1973 is properly implemented".
Moves to put Nato in charge of enforcing the no-fly zone over Libya were "an important step forward", he added.
Mr Cameron again urged Col Gaddafi to go and his "henchmen" to desert.
"My message to Gaddafi, in absolute co-ordination with what (US Secretary of State) Hillary Clinton has said, is that he should leave, he should go. I don't believe there is any future for Libya and the Libyan people with him at its helm, so he should go.
"And the message also to those around him, is that every day you work with this dictator - who has now announced two ceasefires and broken both of them, and continues to murder his own civilians - every day you work for him you are at risk of the International Criminal Court and you are at risk of being found guilty of war crimes.
"The people who are around him and are obeying his orders should realise that that time is up. Don't obey his orders, walk away from your tanks, leave the command and control that you are doing, give up on this regime because it should be over for him and his henchmen."