Four people have been arrested in connection with the attack on the U.S. Consulate in Benghazi, Libya, that left U.S. Ambassador J. Christopher Stevens and three other Americans dead, the top aide to the president of the parliament said Friday.
Those arrested were not directly tied to the attacks that resulted in the deaths, Monem Elyasser, the chief aide to Prime Minister Mustafa Abushagur, told CNN by telephone.
The announcement came as the United States is struggling to determine whether a militant group planned the attack that killed the four Americans.
Elyasser did not release the identities of the four suspects in custody, nor did he detail the allegations against them.
The head of Libya's ruling General National Congress, Mohammed Al-Megaryef, also confirmed the four arrests but declined to say to what group the suspects are linked.
However, the government does now believe the suspects are part of one of the many armed extremist groups operating especially in the eastern part of the country and Benghazi itself, he told CNN.
Authorities also believe the attack was planned and deliberately carried out to inflict maximum damage on key Western interests, particularly the United States, he said.
The government believes the attack was intended to drive a wedge between Americans and Libyans.
Asked what the Libyan government was doing to prevent further attacks, al-Megaryef answered, "We are doing our best to avoid further attacks." But he acknowledged that authorities had little capacity to defend against the powerful extremist groups.
State Department Under Secretary Patrick Kennedy has said that the attack appeared to be planned because it was so extensive and because of the "proliferation" of small and medium weapons at the scene. He was briefing congressional staffers when he offered that theory.
But on Thursday, three U.S. officials told CNN that they have seen no evidence the attack was premeditated.
The FBI is expected to be involved in the investigation against those arrested.
During an interview on CNNI's "Amanpour," Abushagur said Thursday that there had been one arrest early Thursday in Benghazi and that three or four others were being pursued.
"The evidence itself is based on mostly pictures that were taken around the compound at that time, and also through some witnesses," the prime minister said.
Conflicting theories flew in the hours after Stevens, another diplomat and two State Department security officers were killed late Tuesday in the eastern city of Benghazi.
They died amid a protest outside the U.S. Consulate over a film that ridiculed Muslims and depicted the Prophet Mohammed as a child molester, womanizer and ruthless killer.
"I think the degree to which we're able to update this information or deepen it, it's going to be in the context of beginning to interview our employees who are coming out and beginning to participate in the investigation that the Libyans are doing," U.S. State Department spokeswoman Victoria Nuland told reporters Thursday.
The demonstration was one of several protests across the region that day.
Protest as diversion
U.S. officials believe the attackers used the protest as a diversion.
Given what officials know about al Qaeda in Libya, intelligence officials believe it is very unlikely that core al Qaeda was behind the attack, a U.S. intelligence official told CNN on condition of anonymity. The official was not authorized to release the information.
Meanwhile, Shawn Turner, director of communications for U.S. National Intelligence, denied news reports that American officials had been warned of a possible attack.
"This is absolutely wrong," he said. "We are not aware of any actionable intelligence indicating that an attack on the U.S. post in Benghazi was planned or imminent."
The United States is deploying warships and surveillance drones in its hunt for the killers of the diplomatic staffers, and a contingent of 50 Marines has arrived to boost the security of Americans in the country.
The United States and Libya have embarked on a new relationship since rebels toppled longtime dictator Moammar Gadhafi last year.
U.S. and NATO warplanes helped the Benghazi-based rebellion against Gadhafi, who was wanted by the International Criminal Court for charges of crimes against humanity before he was killed in October.
The jihadists suspected in Tuesday night's attack "are a very small minority" who are taking advantage of a fledgling democracy, said Ali Suleiman Aujali, the Libyan ambassador to the United States.
Sources tracking militant Islamist groups in eastern Libya say a pro-al Qaeda group responsible for a previous armed assault on the Benghazi consulate is the chief suspect. A senior defense official told CNN the drones would be part of "a stepped-up, more focused search" for a particular insurgent cell that may have been behind the killings.
Rights groups have raised concerns about the Libyan legal system,