Two car bombs exploded in the Libyan capital, Tripoli, killing two people and injuring several others early Sunday, a security official said. Two others were dismantled safely.

The first bomb went off in a main street near a military college used as a base for former rebel forces, killing two and wounding four, according to the official, who spoke on condition of anonymity because he was not authorized to speak to reporters.

Half an hour later, a taxi parked in a narrow alley near the Interior Ministry exploded, wounding several people.

The official said a third car bomb was discovered, also near the ministry. It was safely defused.

Late Sunday, officials found a fourth car bomb near the military college and dismantled it. Police said they arrested three suspects in connection with the bombings.

The bombings came on the eve of the anniversary of the fall of Tripoli. On August 20, 2011, rebel fighters liberated the city during the eight-month civil war that toppled dictator Moammar Gadhafi's regime.

Gadhafi was captured and killed last October, but many Libyans are convinced that some of his associates remain at large around the country.

After Sunday's blasts, officials blamed Gadhafi loyalists, saying they were plotting attacks and seeking to spread fear among the public and prevent the country from returning to normal.

"I hold former regime aides fully responsible for this cowardly action," said the deputy interior minister, Omar al-Khadrawi, visiting one of the bomb sites. He said "the same kind of bombs and the same tactics and equipment" were used in previously foiled car bombing attacks in Tripoli.

The city's security authorities went on high alert after the bombings, which came just hours before Muslim prayers were to take place at the main Tripoli square for the Eid al-Fitr holiday that marks the end of the holy month of Ramadan.

Attacks have been on the rise in both Benghazi to the east, in Misrata in central Libya, and in the capital, Tripoli.

Last month, Libya elected its first parliament in the nation's first-ever free vote. The house elected a president earlier this month and is now trying to form a government.

The future Cabinet faces a mountain of challenges, including forming a strong national army to unite various militia groups under a central command.