TRIPOLI, Libya (CNN) -- The United States diplomatic office in the Libyan city of Benghazi was attacked Tuesday night, the embassy in the capital of Tripoli said Wednesday.
"Fortunately no one was injured" by the improvised explosive device, the embassy said.
The blast damaged the front gates, the embassy said.
Security forces know the car was used in the attack, in which an improvised explosive device was thrown at the consulate gate, said LIbyan government spokesman Nasser al-Manaa.
Authorities expect to arrest the assailant, al-Manaa said.
There was one local guard outside the building, the government spokesman said.
"The United States deplores the attack on its diplomatic mission in Benghazi. ... We have requested the Libyan Ministry of Interior to increase its security around U.S. facilities in Libya," the embassy said.
The embassy said the attack would not affect the U.S. commitment to Libya.
No one has claimed responsibility for the attack, but it comes less than 24 hours after CNN terrorism analyst Paul Cruickshank predicted such an event in retaliation for the death of a top al Qaeda leader.
U.S. officials said Tuesday that Abu Yahya al-Libi, effectively the terror network's second-highest leader, was dead. He had been focusing on establishing an al Qaeda presence in eastern Libya, several sources said.
A previously unknown group called the Brigades of Omar Abdel Rahman reportedly claimed responsibility for a May 22 grenade attack on an International Committee of the Red Cross building in Benghazi, which is in eastern Libya.
Al-Manaa said the Libyan government has seen the speculation but was not aware of any claim of responsibility and could not confirm that it was linked to al-Libi's death.