The United States is probing whether the deadly attack on its mission in Libya was a well-planned assault by Islamists rather than a rampage by a frenzied mob, officials said on Thursday, as fresh riots broke out in Egypt and Yemen over a controversial film deemed offensive to Islam.
Still scrambling to unravel the facts about the killing of its ambassador to Libya, Chris Stevens, and three other embassy staff almost 24 hours after the incident, the US officials said the attack was "complex" and "they (attackers) seem to have used this (protest) as an opportunity".
The attackers appeared to have used protest over the controversial film as a pretext to stage a major assault using small arms and rockets to overrun the US consulate in Benghazi, they said.
In response to the attacks, US President Barack Obama spoke to his counterparts in Libya and Egypt, seeking cooperation for investigations, as Washington dispatched two naval destroyers to waters off Libya and deployed a 50-strong counter-terrorism team of marines to ramp up security at its Tripoli embassy.
The questions posed by the US officials came as reports from the Libyan capital, Tripoli, said that the government had ordered a probe into the attack.
An announcement said, "An independent judicial committee has been set to carry out an inquiry." An interior ministry spokesman admitted that there were "extremists" in the mob that attacked the consulate.
Senior officials described to reporters that the Benghazi consulate was under a harrowing siege for more than three hours after 10 pm on Tuesday night till Libyan forces moved in to recapture it.
In fact, it took two attempts before Americans were able to regain control of the consulate's main building and had to ask for Libyan help to push out the attackers from the annex.
Security appeared to have collapsed as Libyan groups armed with assault rifles and rockets stormed the complex and set it ablaze.
Libyan and American guards searched in vain for the ambassador amid a barrage of bullets.
The use of gunfire has raised the suspicions of the American officials who are now pressing the Libyans for a joint probe to find out whether a hardline Libyan group, supposedly close to the Al Qaeda ideology, had planned the attack to mark the 9/11 anniversary.
US televising channels showed pictures of Stevens being helped by Libyans inside the compound. The ambassador was later traced to a Benghazi hospital and later his body rushed to the airport to be taken aboard the US aircraft.
Washington may also use unmanned drones stationed in Libya to track militants who might have carried out the attack, US officials said.
The officials warned that investigations underway could change the circumstances of the killings.
A senior administration official in a background briefing conceded that they did not have much details about the circumstances leading to the death of the ambassador, but admitted that prior to storming of the consulate there had been heavy exchange of fire between sections of the protesters and the security personnel guarding the compound.
However, the chairman of the Congress house intelligence committee Mike Rogers minced no words in saying that the attack that killed US ambassador and his staff had all the hallmarks of an Al Qaeda operation.
"Details may still be fuzzy... but clearly it has all the hallmarks of an Al Qaeda operation," the Republican lawmaker told CNN.
Tuesday's attack on the American consulate came amid a wave of protests in Muslim countries against a film made by an Israeli-American director which is deemed offensive to Islam.
US officials on Thursday said that at least three Americans were wounded in the attack that killed the envoy.
Following the attack, Washington has ordered evacuation of its staff in Benghazi to Tripoli.
Though there was no fresh major flare-up, new protests against the film were reported from outside the US missions in Egypt, Morocco, Sudan, Tunisia, Yemen and Iran.
In Egypt, police on Thursday clashed with a stone and bottle-throwing crowd protesting outside the US embassy in Cairo against the film.
According to officials, 16 protesters have been injured in addition to several police officers.
In Yemen, protesters angered by the film stormed the US embassy compound in the capital and burned the American flag. However hours later the invading mobs were cleared by the Yemeni police.
The killing of Stevens plunged the US diplomatic staff into mourning and hundreds of mourners poured into the South courtyard at the US State Department where Obama paid a rare visit and along with Secretary of State Hillary Clinton joined in condolence meeting.