UN officials are probing allegations that Libyan ruler Moammar Gadhafi's forces have abducted, tortured and executed opponents, a special investigator said Wednesday in Geneva.

The UN's special rapporteur for torture, Juan Mendez, told The Associated Press that the investigation has focused on the Gadhafi regime's alleged executions of patients pulled from hospitals, shots fired at crowds of protestors and other uses of disproportionate force.

The investigation "was an urgent action, at the beginning of the troubles," he said. Mendez received complaints from Gadhafi's opponents when his crackdown began in mid-February, he said, and he sent a formal notice to the government demanding information about the allegations.

BBC crew beaten in Libya

Three members of the BBC were detained, beaten and subjected to mock executions by supporters of Moammar Gadhafi, the broadcaster says.

The all-male crew  from the BBC Arabic team were detained Monday by government loyalists at a checkpoint about 10 kilometres south of Zawiya, the focus of some of the fiercest battles in the last few days between rebels and regime forces.

The detainees were moved between several locations and in some cases were held alongside civilian captives who had been severely beaten, said one BBC member, Chris Cobb-Smith.

On Tuesday, the three were driven to a building in Tripoli which they believed was the headquarters of Libya's overseas intelligence service. The men were told by soldiers to bow their heads and line along a wall.

"A man with a small submachine gun was putting it to the nape of everyone's neck in turn. He pointed the barrel at each of us. When he got to me at the end of the line, he pulled the trigger twice. The shots went past my ear," Cobb-Smith said.

The BBC, which disclosed the incident Wednesday, said the men were held for 21 hours before they were released, and that they have since left Libya. 

Liliane Landor, an executive at BBC Global News, said the broadcaster will continue to cover Libya despite the attack on staff.

source: Associated Press

"Those communications are confidential, so I can confirm that we are engaged, but we cannot say more about it," he said.

Mendez, an Argentine lawyer and American University visiting professor of international law in Washington, D.C., said he is teaming up for the probe with the UN's special rapporteur for extrajudicial executions and a panel of experts on disappearances.

He said they would demand information from Gadhafi's regime, and if the responses are inadequate, that would be noted in monthly reports to the UN's 47-nation Human Rights Council based in Geneva.

The council also has ordered a diplomatic-level probe of human rights abuses in Libya and the UN Security Council has ordered a separate probe at the world's first permanent war crimes tribunal into possible Gadhafi-led crimes against humanity.

Mendez said his probe would include looking into reports by aid officials, migrant workers and refugees of Gadhafi's armed soldiers using ambulances to gain admittance to hospitals to remove patients and execute them elsewhere, in an effort to get rid of possible witnesses ahead of Gadhafi's admittance of foreign reporters into Tripoli.

"I can't disclose the names of individuals that were given to us or what happened to them, but I can say that they are the same kind of allegations that you have reported on," Mendez told AP.

"Shooting into the streets against demonstrators, picking them up from hospitals … and also detaining and mistreating them and torturing them," he said. "The torture allegations that we received were more of mistreatment in the street itself, at the demonstrations."

Mendez said Gadhafi's use of torture and illegal detention in the past is well documented, and he might also look into some of those earlier allegations.