Tripoli, Libya (CNN) -- The United States diplomatic office in the Libyan city of Benghazi was attacked Tuesday night, the embassy in the capital Tripoli said Wednesday.
A Libyan security source told CNN a jihadist group that is suspected of carrying out the strike, the Imprisoned Omar Abdul Rahman Brigades, left leaflets at the scene claiming the attack was in retaliation for the death of Libyan al Qaeda No. 2 Abu Yahya al Libi.
"Fortunately, no one was injured" in the improvised explosive device attack, the embassy said.
The blast damaged the front gates, the embassy 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.
U.S. officials said Tuesday that Abu Yahya al-Libi, effectively the terror network's second-highest leader, was dead.
Noman Benotman, a former senior member of the Libyan Islamic Fighting group, said that according to his sources in Benghazi, the leaflets also promised more attacks against the United States.
Benotman, now a senior analyst at the Quilliam Foundation in London, said the attack involved the explosion of a rudimentary homemade device and the operation appears to have been hastily put together. Benotman said on Tuesday that pro al Qaeda groups operating in Libya could use the death of al Libi as a pretext to expand their operations.
The Imprisoned Omar Abdul Rahman Brigades were first heard from when they claimed responsibility for an attack on a Red Cross office in Benghazi late last month. A purported video of the attack was apparently posted on jihadist websites that regularly feature statements by al Qaeda. The video showed several rockets being fired into a building at nighttime. In claiming responsibility, the group stated, "We do not recognize [state] borders when we plan for our operations, and we have prepared a message that will soon reach America in response to polluting the clarity of the defiant city of Derna," according to a translation by Flashpoint Partners, which monitors jihadist websites.
According to several sources, al Qaeda has developed a presence in and around the city of Derna in eastern Libya, where it has recruited and trained militants.
According to a senior Libyan official, there are five "significant" Islamist leaders in eastern Libya. They include Abdulbasit Azuz and Sufian bin Qumu, a former Guantanamo detainee. Of the five leaders, all but Qumu have agreed not to carry out attacks, the official said. The official said Azuz has a training camp outside Derna and the Obeidi tribe, which is responsible for security in that area of Libya, has the camp surrounded.
CNN's Paul Cruickshank contributed to this report.