The US and five European nations on Tuesday called on rival Libyan groups to endorse a deal at UN-led negotiations to resolve the country's ongoing crisis.

Britain, France, Germany, Italy, Spain and the US urged the parties to sign a proposed deal at talks in Morocco and called for peace in the country.

"We urge all Libyan parties to sign in the coming days the political agreement presented by the UN," said a joint statement from the nations.

The six countries said they welcomed the proposal and supported the formation of a Government of National Accord.

"We consider this document a thoughtful, well-balanced basis for agreement that meets the urgent expectations of Libyan people and secures the unity of Libya," they said.