Tripoli's self-declared government has said it will not cling to power but will peacefully oppose a U.N.-backed unity government that arrived in the capital this week from Tunisia.
Western powers hope the unity government will seek foreign support to confront the Islamic State militant group, deal with migrant flows from Libya towards Europe and restore oil production to shore up its economy.
But the new government, which held its first meetings in Tripoli on Thursday at a heavily guarded naval base, has failed to win backing from Libya's two rival pairs of governments and parliaments, one based in Tripoli and one in the east.
The head of the Tripoli-based National Salvation government, Khalifa Ghwell, has vehemently opposed any transfer of power. But a statement posted late on Thursday on the government's website struck a milder tone, saying opposition would be "by peaceful and legal means without use of force or incitement to violence".
"We will not cling to power," the statement said. "I demand that the revolutionaries, civil society and the senior clerics be given the opportunity to take the necessary decisions to avoid bloodshed and find a solution to the Libyan crisis."
In a boost for the new unity government and its leadership, or Presidential Council, 10 western Libyan towns and cities said they welcomed and supported its arrival.
The European Union has imposed asset freezes on Ghwell and the heads of the parliaments in Tripoli and the east, citing their role in obstructing the unity government. Those sanctions took effect on Friday.
The new government's seven-member Presidential Council is trying to take control of institutions in Tripoli and to secure the backing of the capital's many armed groups.
An official at the foreign ministry in Tripoli said security forces loyal to the Presidential Council had secured the ministry building and that the minister previously appointed by the National Salvation government had left peacefully.
Tripoli has been mostly calm since the Council members arrived on Wednesday. They travelled to Tripoli by ship after opponents shut down the capital's air space to prevent them from flying in.