A United Nations fact-finding mission arrived in the capital city of Tripoli on Wednesday to look into reports of human rights violations by Libyan authorities.

The UN delegation raised a number of issues, including the "indiscriminate bombing of civilian areas, civilian casualties, torture, the use of mercenaries and other questions of the sort," said delegation leader Cherif Bassiouni, who is from Egypt.  

Death toll rising

The death toll in Libya after more than two months of violence could reach 30,000, an Obama administration official said Wednesday.

Gene Cretz, the U.S. ambassador to Libya, said it is very hard to gauge how many people have died in strongman Moammar Gadhafi's crackdown on protesters and the subsequent fighting between rebels and pro-government forces. But he said U.S. officials have seen figures ranging from 10,000 to 30,000.

"I don't think we're probably going to get an accurate number until we really get more hands-on experience on the ground," Cretz told reporters at the State Department in Washington. "We just have no sense of the scale of this thing until it's over."

Elsewhere in Libya, forces loyal to leader Moammar Gadhafi fired mortar rounds into the west side of Misrata, rebel sources told Reuters.

The offensive represented a new tactic for the pro-Gadhafi forces, who have previously confined their attacks to the port area on Misrata's rebel-held east side.

Misrata has been under siege by Gadhafi's military for almost two months.

Italy puts 4 jets at NATO's disposal

In another development, Italy announced it would make four of its Tornado jets available for NATO to carry out airstrikes against military targets in Libya.

A few days ago, Italy reversed its earlier position that it would not take part in any airstrikes. Italian officials said the country's change of heart was prompted by Gadhafi's continued attacks on civilians in Misrata.

Italian Defence Minister Ignazio La Russa said four jets will be used "for targeted action against specific and selected" military targets. Italy has also allowed other countries to use its domestic air bases to conduct sorties over Libya. 

On Wednesday, an F-16 jet taking part in the NATO-led Libyan mission crashed on landing at a base in Italy after flying in from another base in Italy.

Reports said the pilot of the United Arab Emirates jet ejected safely but the aircraft was damaged.   

With files from The Associated Press