Masked gunmen attacked a police station in the Libyan capital on Thursday, April 4, tying the hands of four officers on duty and releasing three detainees, security sources said, according to Reuters.

About 10 armed men forced their way into the police station in southwest Tripoli's Abu Salim neighborhood at dawn and freed three of five men in custody there, one security official said.

"These were criminals. They attacked the police station firing at it with rifles," said a second security source, adding that security forces were searching for the culprits.

The head of the Tripoli council, Sadat al-Badri, and Colonel Mahmoud Sharif, in charge of security in the capital, visited the station and spoke to the policemen who had been tied up.

Since the end of the 2011 uprising that toppled Muammar Gaddafi, Libya's new rulers have struggled to control armed groups which refuse to lay down their weapons and often take the law into their own hands.

Security remains precarious across the North African oil-producing country, where weapons are plentiful. On Sunday, an adviser to Prime Minister Ali Zeidan was grabbed from his car by unidentified assailants on the outskirts of Tripoli.

The same day, an armed group controlling a Tripoli prison stormed the justice ministry, an attack the justice minister said took place after the group was ordered to hand over the jail to the authorities.