Forces loyal to Libyan leader Muammar Qadhafi continue to advance in the country's eastern oil heartland, and are moving into an advantageous position from where they could threaten Benghazi, the epicentre of the anti-Qadhafi uprising.
Pro-government forces on Saturday were in control of Brega, a strategic oil town which has an export terminal.
But the status of Ras Lanuf, known for its oil refinery remains unclear. Opposition forces said they were in control of the town by afternoon on Saturday, contradicting claims in the morning by the pro-Qadhafi camp that government forces were holding the town.
The battle for Ras Lanuf, and then for the neighbouring city of Ajdabiyah, could prove crucial. From Ajdabiyah, Benghazi is only one-and-a-half hours drive away. There has been a fresh effort by the dissidents to strengthen Benghazi's southern defences, but it is doubtful whether these will hold in the face of heavy artillery barrages, backed by possible aerial bombardment.
The deeper advance is extending the regime's supply lines. But without heavy weaponry and support from the air, it is unlikely that the opposition will be able to exploit this vulnerability.
As it loses ground, the dissident's are sharpening the calls for international intervention. “Where is the West? How are they helping? What are they doing,” Al Jazeera quoted an angry fighter as saying.
The desperation follows the inability of the European Union on Friday to agree on a French proposal to legitimise air strikes against regime targets if it uses chemical weapons or attacked peaceful protesters.
The eastern advances by pro-Qadhafi forces follow its success in crushing the rebellion in Zawiyah, 50 km to Tripoli's west. Al Jazeera is reporting that on Friday, foreign journalists brought by the government to the city saw several buildings burnt. Regime loyalists positioned in advance in the city chanted: “I love Qadhafi”.
Protesters still held Misurata, but they were expecting a heavy regime assault on Libya's third largest city, 200 km east of Tripoli.