Former rebels who fought the Libyan dictator Col. Muammar el-Qaddafi and are now challenging Libya’s shaky central government have announced the creation of their own oil company to sell crude from oil fields and port terminals they currently occupy.

For the past three months, most of Libya’s oil production and exports have been halted by loosely aligned militias in the eastern region of the country that are pushing for autonomy. They have made Prime Minister Ali Zeidan’s government, which has repeatedly threatened to arrest the occupiers, look increasingly impotent, which emboldened eastern political leaders, including some former rebels, to form an autonomous regional government last month.

The establishment of a regional oil company was largely seen as a symbolic move since few oil shipping companies would rush to challenge Tripoli authorities and Western governments that want to see a central government succeed. But the company represents another escalation of tensions over the country’s most strategic economic asset.

“It’s just another sign that the political process of forming a national government is in deep disarray,” said David L. Goldwyn, the State Department coordinator for international energy affairs from 2009 to 2011.