Updated

BREGA, Libya -- Mutinous army units in pickup trucks armed with machine-guns and rocket launchers deployed around the strategic oil installation at Brega Thursday, securing the site after the opposition repelled an attempt by loyalists of Muammar al-Qaddafi to retake the port in rebel-held east Libya.

Government warplanes launched a new airstrike on the town in the morning, according to witnesses. It was not clear what they targeted, but it was likely an airstrip that belongs to the huge oil complex on the Mediterranean coast. There were no reports of casualties.

"We are in a position to control the area and we are deploying our forces," a rebel army officer in Brega told The Associated Press, speaking on condition of anonymity because he was not authorized to talk to the media.

Wednesday's battle at Brega halted for now the regime's first counteroffensive on the opposition-held eastern half of the country. It also underlined the deadlock that Libya appears to have fallen into more than two weeks into its upheaval.

Qaddafi's forces seem unable to bring significant strength to dislodge rebels from the territory they hold -- but the opposition does not have the capability to go on the offense against Qaddafi's strongholds in the west, including the capital.

In further pressure on the Libyan leader, the top prosecutor at the Netherlands-based International Criminal Court said Thursday he would investigate Qaddafi and his inner circle, including some of his sons, for possible crimes against humanity in the violent crackdown on anti-government protesters.

Luis Moreno-Ocampo said Qaddafi and several commanders and regime officials had formal or de facto control over forces that attacked protesters. There will be "no impunity in Libya," he vowed.

Opposition leaders are pleading for foreign powers to launch airstrikes to help them oust Qaddafi as the United States moves military forces closer to Libyan shores to put military muscle behind Washington's calls for Qaddafi to give up power immediately.

But the Pentagon on Wednesday tried to play down the idea of using military force in Libya, including a "no-fly zone" that Defense Secretary Robert Gates said would first require attacking Qaddafi's government.

"Let's just call a spade a spade: A no-fly zone begins with an attack on Libya to destroy the air defenses," Gates told lawmakers. He added that the operation would require more warplanes than are on a single U.S. aircraft carrier.

At Brega, army units that have joined the opposition moved in to keep security after Wednesday's battle, waged by citizen militias from nearby towns and cities. Despite having little central organization, the anti-Qaddafi fighters -- armed with automatic weapons and some heavy machine guns and rocket launchers -- was able to repel a force of several hundred regime troops that attacked after dawn.

Farj Lashrash, a soldier with the opposition, said the rebel fighters had captured 10 pro-Qaddafi soldiers since last night.

The troops came in from the opposition stronghold of Benghazi, 140 miles northeast of Brega. Dozens of the rebel forces, armed with Kalashnikov rifles and dressed in camouflage army uniforms with checkered keffiyehs around their necks or heads fanned out around Brega, which has a port, airstrip, oil installation and a small town. They were backed by at least a dozen pickup trucks with machine-guns bolted onto their beds or rocket launchers in tow.

There was no sign of any pro-Qaddafi forces around Brega. Aside from the airstrike, the area was calm. No casualties from the airstrike were reported, but a few rebel fighters were rushed to the hospital with wounds after a mortar they were handling exploded.

In the nearby rebel-held town of Ajdabiya, which sent fighters to the battle, morgue officials said the death toll from the Brega fighting rose to 14 from at least 10 a day earlier.

The western gate of the town was reinforced with heavy weaponry Thursday against any further attempts by government forces to retake control of the area. Rebels positioned a tank, four anti-aircraft guns mounted on pickup trucks and four rocket launchers at the gate.

Brega is the second-largest petroleum and natural gas facility in OPEC-member Libya and has been held by the opposition since last week.

Amid the chaos sweeping the country, exports from the country with Africa's largest proven oil reserves have all but stopped. Crude production in the southeastern oil fields that feed the facility at Brega has been scaled back because storage facilities there are filling up.

The uprising has sent world oil prices spiking to the highest levels in more than two years, above $100 per barrel. Overall, Libyan crude production has dropped from 1.6 million barrels per day, nearly 2 percent of world consumption, to as little as 600,000 barrels per day.

On Thursday, oil prices eased a bit to around $101 per barrel from around $102 on Wednesday.

"In the last 24 hours, we had a bit of a panic here," oil company employee Osman Rajab told the AP. "Now they (the rebel army) are trying to control the industrial areas," he said, referring to the oil complex.

At the edge of Brega's massive oil facility, the rebel army set up a line of defense, with soldiers, four pickup trucks mounted with machine guns and one truck towing a rocket launcher.

Wednesday's battle was fought primarily by a ragtag popular militia -- armed men from nearby towns and cities who rushed in in pickup trucks and overpowered several hundred pro-Qaddafi forces after chasing them into a university on the outskirts of the town.

For the past week, pro-Qaddafi forces have been focusing on the west, securing Tripoli and trying to take back nearby rebel-held cities. But the regime has seemed to struggle to bring an overwhelming force to bear against cities largely defended by local residents using weapons looted from storehouses and backed by allied army units.

Pro-Qaddafi forces succeeded over the weekend in retaking two small towns. But the major western rebel-held cities of Zawiya and Misrata, near Tripoli, have repelled repeated, major attacks -- including new forays against Zawiya on Wednesday.

Zawiya was quiet Thursday, and residents have set up defenses at the city entrances, said resident Alaa al-Zawi, an opposition activist. "Our information is that there is a big (pro-Qaddafi) force amassed on the eastern side of the city," he said. "There might be an attack but we are ready to repulse it."

He said the city has enough food and water to last up to six months, though the worry is lack of medicine if fighting resumes.

Qaddafi spoke Wednesday in Tripoli, warning the U.S. or other Western powers not to intervene. He vowed to turn Libya into "another Vietnam," and said any foreign troops coming into his country "will be entering hell and they will drown in blood."

In a speech to chanting and clapping supporters in Tripoli, Qaddafi vowed to fight on "until the last man and woman. We will defend Libya from the north to the south."

He lashed out against Europe and the United States for pressuring him to step down, warning that "thousands of Libyans will die" if U.S. and NATO forces intervene in the conflict.

"We will distribute arms to 2 or 3 millions and we will turn Libya into another Vietnam," he said.

In Benghazi, Libya's second-largest city and the stronghold of the rebellion in the east, a self-declared "interim government council" formed by the opposition called Wednesday on foreign nations to carry out airstrikes on non-Libyan African mercenaries that Qaddafi has used in his militias to put down the uprising. Council spokesman Abdel-Hafiz Hoga said the council urged airstrikes on the "strongholds of the mercenaries .... used against civilians and people."

The council was announced Wednesday by opposition leaders, headed by Qaddafi's former Justice Minister Mustafa Abdel-Jalil, who joined the uprising.

The turmoil in Libya has set off a massive exodus of 180,000 people -- mostly foreign workers in Libya -- who have fled to the borders, U.N. refugee agency spokeswoman Melissa Fleming told the AP. European nations and Egypt launched emergency airlifts and sent ships to handle the chaotic crush.

More than 77,000 so far have crossed in Egypt, and a similar number into Tunisia -- with about 30,000 more waiting at that western border.

Some Somali and Eritreans workers around Benghazi are feeling "hunted" as they are being mistaken for mercenaries hired by Qaddafi, she said, while regime forces appear to be targeting Egyptians and Tunisians, apparently believing they triggered the uprising.