Diplomatic missions here in the Libyan capital are observing the strictest security procedures following suspicions that the bombers behind last Tuesday’s blast at the French Embassy have rigged a second car with explosives and are hunting for another high-profile Western target.

Embassy protection teams and private security contractors working with foreign businessmen and nongovernmental organizations are on high alert, and the United Nations compound on the outskirts of Tripoli has introduced onerous security measures and placed severe restrictions on the movement of their diplomats.

The French Embassy wasn’t the only target on Tuesday—the second target was, according to diplomatic sources, the British Council, a government-funded educational body under the aegis of the British Foreign Office. That attack was thwarted by security guards; the bombers were foiled as they were preparing to park a rigged vehicle in front of the compound gate, diplomatic sources say.

A British Embassy spokesman said they could neither confirm nor deny that a bombing attempt on the British Council took place. "It would be inappropriate for us to comment while investigations are under way."

The blast at the French Embassy in the smart residential district of Hay Andalous injured two French security guards, one severely, and wounded several residents in neighboring houses, including a teenage girl who sustained serious spinal injury. It was the first major attack on a foreign mission in the capital since the toppling 18 months ago of Col. Muammar Gaddafi and the first on a diplomatic building in Libya since the assault last September on the U.S. consulate that left U.S. Ambassador Christopher Stevens and three other Americans dead.

According to diplomatic sources, a French forensic team (led by a magistrate dispatched from Paris within hours of the attack) believes the bomb, which was forceful enough to hurl debris three blocks away, consisted of 12 artillery shells containing high density explosive and was detonated by remote control. There was evidence of a circuit board. The bomb was packed in a white Audi and the only substantial part of the car left was the engine block.

Security sources compare the attack to al Qaeda-style car bombings seen in Iraq, arguing that the bomb was far more sophisticated than previous explosive devices seen in Libya since Gaddafi’s fall. Al Qaeda car bombs in Iraq frequently employ artillery or mortar shells and the same is true in Afghanistan, although recently Taliban bombers have been using ammonium nitrate in place of artillery shells.

“We clearly have a proficient bombmaker in town,” says a European security official. “And I doubt he’s here for one hit. Once you get someone in like that you utilize his services to the maximum.” Last autumn, U.S. security sources told The Daily Beast that several “mechanics”—a term for bombmakers—had been moved by al Qaeda–connected groups from Somalia to Mali, and they expressed fears that eventually one or two may might make their way to Libya.

Previous car bombings in Libya have lacked the power of the blast at the French embassy. Aside from a series of small bombs planted under the cars of former Gaddafi security officials in Benghazi in the autumn and earlier this year, other blasts have been targeted at Sufi Muslim shrines—the last in April destroying the Al-Andalusi Mausoleum in Tajoura, 15 kilometers from Tripoli—or government buildings, as on March 5 when a car bomb exploded in front of a government building in Beida, in eastern Libya, injuring a guard and causing slight damage.

Libyan and foreign security sources blame the attacks on former Gaddafi officials or hardcore revolutionary militiamen intent on score settling. The blasts at Sufi shrines are put down to Salafists focused on what they see as symbols of Muslim apostasy. But the attacks on government buildings and the blast at the French embassy—as well as the assault on the U.S. consulate—are being tied by Western security sources to jihadists, who may have connections or associations with al Qaeda groups.

A video statement appearing to foreshadow the French Embassy bombing was uploaded to YouTube by an Islamic television channel just before the French embassy blast. It isn’t clear if the statement made by a group calling itself the Mujahedeen Brigade was uploaded several hours or several days before the explosion. “The target was the infidels’ headquarters [the French Embassy], and from now on our jihadist operations are transferred to Tripoli. No embassy, company or building occupied by the westerners is safe from our harm,” the speaker on the video states.

Four days before the embassy attack, Al Qaeda in the Islamic Maghreb threatened retaliation for the French intervention in Mali against an Islamist insurgency in the African state.

Libyan government officials are remaining tight-lipped about the embassy attack, trying to avoid the chaos in the immediate days following the assault on the U.S. consulate when Libyan leaders contradicted each other and offered clashing explanations about who was behind the assault on the consulate in Benghazi. In order to curtail any confusion, Prime Minister Ali Zeidan’s office announced that only the Libyan premier and the justice, interior and defense ministers had authority to speak about the bombing.

But that hasn’t completely halted contradictions being made. Some government officials told local media that suspects had been arrested, the number ranging from four to 17. But the interior and defense ministries said they had no knowledge of arrests being made.

Since Ali Zeidan came into office last year, there have been no significant updates by the government on the progress a probe is making into the assault on the U.S. consulate and death of ambassador Stevens. Justice Minister Salah Marghani says he can’t confirm that there are any suspects for that attack currently being held.

The French appear to have been less patient than the Obama administration was last autumn in trying to establish the facts on the ground. While an FBI team waited weeks before being given the go-ahead by the Libyan government to inspect the razed U.S. consulate, Paris gave the Libyan government no choice about sending in a forensics team. Asked about the contrast and how come French investigators got in quickly, a French diplomat commented: “That question is better directed to the Americans. We just told the Libyans that we had sent a forensics team and informed them when they would be landing.”

The magistrate-led 10-strong team was scouring the bombsite for clues by the next morning and interviewing local residents. As they investigated, there were more security scares in the capital, setting Tripoli on edge. On Friday night a bomb threat against a Libyan movie awards festival at the Radisson Blu Hotel led to the evacuation of diplomats and movie aficionados. And at the weekend elsewhere in Libya there was a bomb attack on a police station in Benghazi, and unidentified gunmen attacked the headquarters of a security battalion in Derna, killing one of its members. Following the attack, a car bomb containing 50 kilos of explosives was discovered. On April 28, hardcore militiamen blocked the Libyan foreign ministry, demanding that all Gaddafi holdovers working there be immediately fired.

With Libya reeling from the embassy attack and the blockading by hardcore militiamen of the country’s key interior and foreign ministries, Prime Minister Zeidan lamented at a press conference yesterday the “disorder and terror” striking the struggling country—but insisted Libya could persevere, arguing it was still better off than Afghanistan or Iraq.

Libya’s perilous security situation is not being helped by an influx of Islamist fighters from Mali escaping the French-led intervention there. At the weekend, the Chadian president, Idriss Deby, complained Libya isn’t doing enough to prevent these fighters from using Libya as a training ground for new recruits.