Four Libyan policemen were wounded on Wednesday when a bomb exploded in front of their station in the eastern city of Benghazi, security sources said.

"The blast coincided with a traffic police vehicle passing in front of Al-Fwihet station," police officer Adel Jibril told Agence France Presse.

Unknown attackers fired at a convoy transporting United Nations personnel east of the Libyan capital on Wednesday, a U.N. spokeswoman told Agence France Presse, adding that no one was hurt.

"Yes, indeed there has been an incident. A U.N. convoy was shot at. There were no injuries," said Radia Achouri, confirming reports that the attack took place in Khoms, 100 kilometers (60 miles) east of Tripoli.

Libya on Wednesday reiterated its call for the extradition of slain Libyan strongman Moammar Gadhafi's son Saadi from Niger, which has granted him asylum since September 2011 on "humanitarian" grounds.

"The Libyan party has noted the threat posed by the presence in Niger of members of the former Libyan regime," said a government statement issued after a visit to Niamey by Libyan Prime Minister Ali Zeidan.

The trial of Moammar Gadhafi's last prime minister al-Baghdadi al-Mahmoudi, accused of aiding the state to kill civilians and financial crimes, opened in a Libyan court on Monday.

A judge read out the charges against Mahmoudi which included "abusing public funds" and "committing acts aiming to unjustly kill people" during the 2011 uprising that toppled Gadhafi.

Egyptian authorities have detained a suspected terror network ringleader whose operatives are believed to have carried out a deadly attack on a U.S. mission in Libya, a report said Friday.

Mohammed Jamal Abu Ahmed -- a former member of the Egyptian Islamic Jihad, who was freed from prison in March 2011 following the ouster of Egyptian leader Hosni Mubarak -- was captured in the past week, the Wall Street Journal reported, citing unnamed U.S. officials.

Ziad Takieddine, a Franco-Lebanese businessman who has been charged with corruption in the "Karachi" kickbacks affair is also being investigated for suspected money laundering after being detained with 1.5 million euros in cash, it emerged Thursday.

Judicial sources said Takieddine, who is allegedly embroiled in a string of illegal political financing scandals in France, had been caught with the money on a private flight out of Libya in March 2011, prior to the overthrow of Libya's then President Moammar Gadhafi.

Almost 200 Libyan prisoners have escaped from a jail in the southern town of Sabha in unclear circumstances, officials said on Wednesday.

"One hundred and ninety-seven prisoners escaped the prison of Sabha yesterday (Tuesday)," a member of the security services told AFP on condition of anonymity.

A Tunisian suspected of involvement in an attack on the U.S. consulate in Benghazi in which the U.S. ambassador to Libya was killed is refusing to be interrogated by FBI agents, his lawyer told Agence France Presse.

"They wanted to interrogate him as a witness, but he has refused," Abdelbasset Ben Mbarek said late on Monday, referring to his client Ali Hamzi, and denouncing what he called "interference" in the Tunisian judicial system.

U.S. envoy to the U.N. Susan Rice Tuesday failed to quell a row with Republican lawmakers over the attack on a US mission in Libya that may damage her hopes of becoming the next secretary of state.

After hour-long talks, the lawmakers dug in their heels saying they were more troubled than ever over the U.S. administration's explanation, led by Rice, about the September 11 attack on the U.S. mission in Benghazi.

Libya's deputy interior minister said Wednesday that gunmen assassinated the security chief of the eastern city of Benghazi overnight.

Omar al-Khadrawi said National Security Chief Col. Farag al-Dersi was shot dead while returning from work.