US Secretary of State John Kerry has met the British Foreign Secretary William Hague and the Libyan Prime Minister Ali Zeidan in London to discuss the security situation in Libya.
Rebels helped topple and kill veteran dictator Muammar Gaddafi in 2011, but have since banded into militias carving their own fiefdoms, each with its own ideology and regional allegiance.
Following the meeting, Kerry told reporters that the US and the UK would continue to support Libya, following weeks of violence in the country
"We talked to the prime minister today about the things we can do together, the United Kingdom and the United States and its other friends, in order to help Libya to achieve the stability that it needs," Kerry told a press conference.
"Libya has gone through great turmoil, particularly after the course of the last weeks," Kerry added.
"And the Prime Minister informed us of a transformation that he believes is beginning to take place and could take place because the people of Libya have spoken out and pushed back against the militias.
"So this is a moment of opportunity where there's a great deal of economic challenge, there's a great deal of security challenge."
Libya's government announced plans last Tuesday to remove the groups from the capital and eventually integrate them into the security forces, after a weekend of deadly clashes between fighters and residents.
Hundreds of residents then on Friday called on Libyan armed groups still in Tripoli to follow other groups and withdraw.
Zeidan stressed that country had lately "done a lot to get rid of the militias" and praised the work of allies who had committed to help Libya.
As a result, he predicted that Libya would become "an active contributor on the world arena."
Foreign Secretary Hague pledged Britain's support to help Libya establish security and democracy and, along with Kerry, welcomed the withdrawal of armed militias from Tripoli.