Twin car bomb blasts killed two people at dawn on Sunday in the Libyan capital, security officials said, blaming loyalists of now slain dictator Muammar Gaddafi for the attacks.
Tripoli's security chief Colonel Mahmoud al-Sherif told AFP the bombs were detonated by remote control and struck near a military academy and the interior ministry.
"They were two car bombs detonated by remote control," Sherif said, adding that four people were also wounded.
The attacks struck on the first day of the Eid al-Fitr festival that ends the fasting month of the holy Ramadan.
The first car bomb blew up at 6:00 am (04:00 GMT) near a military academy on Omar al-Mokhtar Avenue -- a main Tripoli thoroughfare that was closed briefly to traffic -- and the second near the interior ministry.
An AFP correspondent said checkpoints were set up on other major streets in the city centre.
Earlier this month, three men suspected of preparing bomb attacks were killed during a police raid near Tripoli but several of them managed to flee, authorities said.
According to Sherif, Sunday's attacks were orchestrated by "the same sleeper cell," because the explosives and methods used were the same as in an attack in central Tripoli on August 3.
Deputy Interior Minister Omar al-Kadhrawi told AFP that security services had been tipped off on possible attacks being carried out in Libya.
"For the past three days, we had information that such attacks could take place, but it is difficult to control everything because the country is awash with weapons," he said.
Earlier this month. gunmen shot dead a high-ranking defense ministry official in the city -- Libya's second largest -- one of his sons told AFP. A bomb blast also shook the military intelligence building in Benghazi, which was the cradle of the uprising.