The Libyan air force has bombed the oil refinery and port town of Marsa El Brega as battles between forces loyal and against Muammar Gaddafi raged in several towns across the North African country.

“We just watched an air force jet … fly over Brega and drop at least one bomb and huge plumes of smoke are now coming out ,” Al Jazeera’s Tony Birtley said on Wednesday.

The warplane from Gadhafi’s air force struck a beach near where the two sides were fighting at a university campus.

A witness said the blast raised a plume of sand from a dune but caused no casualties, apparently an attempt to scare off the anti-Gadhafi fighters besieging regime forces in the campus.

“All the fighters here are massing. We understand that something like 250-300 pro-Gaddafi fighters are inside Brega and they are being surrounded,” our correspondent said.

The bombing of Brega and reports about the fall of Gharyan and Sabratha towns in the country’s northwest to pro-Gaddafi forces came as Gaddafi appeared on state television once again.

Located between Gaddafi’s hometown of Sirte — still under government control — and the opposition-held eastern port of Benghazi, Brega also sits near ethnic fault lines between tribes loyal to Gaddafi and eastern groups opposed to him.

“They tried to take Brega this morning, but they failed,” Mustafa Gheriani, a spokesman for the February 17th Coalition, an anti-government group, told the Reuters news agency.

“It is back in the hands of the revolutionaries. He is trying to create all kinds of psychological warfare to keep these cities on edge.”

Al Jazeera’s Jacky Rowland, reporting from Benghazi, Libya’s second largest city now controlled by rebels, described the situation in the Brega region as fluid.

” I think it’s fair to say that here is a fair amount of fighting going on in that area,” she said.

Meanwhile, the rebel National Libyan Council in east Libya called for UN-backed air strikes on foreign mercenaries used by Gaddafi against his own people.

Hafiz Ghoga, a spokesman for the council based in Benghazi, told a news conference that Gaddafi was using “African mercenaries in Libyan cities” which amounted to an invasion of the oil producing North African nation.

“We call for specific attacks on strongholds of these mercenaries,” he said, but added: “The presence of any foreign forces on Libyan soil is strongly opposed. There is a big difference between this and strategic air strikes.”

Wednesday’s developments come as the US sent warships to the region as part of a Western effort to pile more pressure on Gaddafi to stop his violent crackdown and step aside.

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