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

As the team began its work, Gadhafi’s forces resumed bombarding the port in Misrata 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 Cherif Bassiouni, an Egyptian legal expert and member of the U.N. commission, Reuters news service reported.

In Misrata, 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 Gadhafi’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 Misrata was destroyed, Romero said.

The bombardment of the port by Gadhafi’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 Misrata, an assertion disputed by human rights groups, aid agencies and video evidence. It says that it is fighting armed gangs and al-Qaida militants in the city, that the port is being used to bring in arms and terrorists and that residents are being held hostage by the rebels.

In the Western, or Nafusa, mountains, where Gadhafi’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 Gadhafi’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 Gadhafi 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 Gadhafi’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, Gadhafi’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 it expected to be given, Reuters quoted Bassiouni 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 Gadhafi 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 armed 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.

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 Gadhafi’s government are beginning to bite.