A team of U.N. investigators met with Libyan officials here Wednesday and said it would be seeking answers to allegations that Moammar Gaddafi’s government has committed human rights violations.

As the team began its work, Gaddafi’s forces resumed bombarding the port in Misurata with Russian-made truck-mounted Grad missiles, disrupting the delivery of humanitarian aid to the besieged rebel-held city, as well as evacuation of the wounded.

“We have a number of questions dealing with indiscriminate bombing of civilian areas, civilian casualties, torture and the use of mercenaries and other questions,” said M. Cherif Bassiouni, an Egyptian legal expert and member of the U.N. commission, Reuters news service reported.

In Misurata, rebels had warned that their hard-won gains of the past week would be at risk unless NATO stepped up its aerial assistance. On Wednesday, they were slightly happier, after NATO airstrikes pounded Gaddafi’s forces attacking the port and forced them to withdraw.

“Several NATO aircraft were directed to the area, and following careful assessment of the risk to civilians, our pilots struck,” NATO spokeswoman Carmen Romero said in Brussels.

Damage assessments showed that six military vehicles and seven “technicals” — civilian trucks equipped with machine guns or rocket launchers — were hit. One surface-to-air missile site near Misurata was destroyed, Romero said.

The bombardment of the port by Gaddafi’s forces in the past two days has worsened the humanitarian situation in the city, the E.U. commissioner for humanitarian aid said in Brussels.

“The port shelling hampers vessel rotation and therefore hinders further evacuations,” commissioner Kristalina Georgieva said. “The delivery of food, medical supplies and other relief items has been interrupted, and it is close to impossible for our humanitarian partners to evacuate the wounded and civilians by sea.”

Nevertheless, the International Organization for Migration said it had taken advantage of a lull in the shelling to evacuate 935 foreign workers and Libyans to the rebel stronghold of Benghazi.

The Libyan government routinely denies even using artillery, rockets or mortar shells in Misurata, an assertion disputed by human rights groups, aid agencies and video evidence. It says that it is fighting armed gangs and al-Qaeda militants in the city, that the port is being used to bring in arms and terrorists and that residents are being held hostage by rebels.

In the Western, or Nafusa, mountains, where Gaddafi’s forces are fighting an uprising led by ethnic Berbers, rebels said the army had fired Grad rockets into the town of Zintan, 100 miles southwest of Tripoli, on Wednesday.

In Washington, the U.S. ambassador to Libya, Gene Cretz, accused Gaddafi’s forces of laying siege to mountain towns in recent days, “apparently attempting to starve them into submission.” Ethnic Berbers have long faced discrimination and suspicion under the Gaddafi regime, tribal experts say.

“They’ve been especially brutal in going after those mountain towns,” Cretz told journalists.

Cretz said diplomats were also hearing that more officials in Gaddafi’s inner circle want to break away but fear doing so. “They’re afraid for their lives. They’re also afraid for their families,” he said. The West scored a major coup when Musa Kusa, Gaddafi’s foreign minister, defected last month, but there have been no high-profile defections since then.

In Tripoli, the U.N. team said it would press for access to prisons, hospitals and areas of the country where it suspects rights abuses are taking place.

Asked what access the team expected to be given, Bassiouni was quoted by Reuters as saying: “We don’t know that yet. We have put it all in writing and stated it verbally, and we intend to push for it.”

The United Nations, Western governments and some Arab states accuse Gaddafi of ordering his security forces to kill hundreds of civilians who rose up against his four-decade rule. The government says it was merely defending itself against gangs that took up arms, burned police stations and were intent on violently overthrowing the state.

Bassiouni said he would also raise the issue of foreign journalists being held in Libya. The authorities are thought to be holding 10 foreign journalists, including three Americans, one Spaniard, a South African and a Canadian. Libyan officials say they detain journalists only if they are in the country illegally.

“We have asked for an opportunity to visit them and to ask why they are not being released,” Bassiouni said.

The inquiry commission, which has carried out field investigations in rebel-controlled eastern Libya, as well as on the country’s borders, was set up in February by the U.N. Human Rights Council and is due to submit its report by June.

Meanwhile, armed police and soldiers have been deployed to keep the peace at gas stations throughout government-held western Libya, as lines stretch hundreds of yards and waiting times to fill a tank often last days.

The lines represent the most obvious sign that international sanctions against Gaddafi’s government are beginning to bite. Fistfights have broken out at some gas stations, but it is not clear who will benefit politically from the public frustration.

“Some people are angry against the government. Some people are angry against Europe, against Britain and France,” said Fauzi Aribi, a businessman and Gaddafi supporter in Zuwarah, west of Tripoli, referring to the effect of the gasoline shortage. “Everybody has a different way of taking this.”

Also Wednesday, foreign journalists in Tripoli were taken to see a specially organized event in the town of Sbia, 30 miles south of the capital, where 17- and 18-year-old schoolgirls were shown how to use AK-47 assault rifles.

The event was supposed to show that civilians are armed and willing to resist any invasion by NATO ground forces.

“I want to defend my country from the crusader enemy . . . and the rats,” said Salmeen Faroun, 18, referring to NATO and the rebels, adding that she wanted to become a doctor so she could cure people “infected by the uranium from European missiles.”

Staff writer Mary Beth Sheridan in Washington contributed to this report.