WASHINGTON // Two men arrested over the murder of the US ambassador to Libya in an attack on the American consulate in Benghazi may be linked to Al Qaeda in the Islamic Maghreb.
There is "some connection" between the Islamist militant group and the two Tunisians detained in Turkey on Wednesday night, the United States defence secretary Leon Panetta said.
The two Tunisians are believed to have been on a watch list provided by Washington to Turkish authorities. Officers from Turkey's anti-terrorist squad detained them at Ataturk Airport in Istanbul, trying to enter the country on fake passports.
The ambassador, Chris Stevens, and three other Americans died in the attack on the consulate last month, in what was initially thought to be a protest against the anti-Muslim film Innocence of Muslims that escalated out of control.
But the date of the attack - the anniversary of the September 11 attacks in New York and Washington in 2001 - and the use of heavy weaponry suggest the attack was not spontaneous. US intelligence officials now believe it was planned, and militant groups simply took advantage of protests at the consulate.
The change of opinion has raised questions about the US administration's handling of the attack and its aftermath, and turned it into an issue in the US presidential campaign. Republicans say there was a deliberate attempt to mislead the American public and cover up failures to heed security warnings and pick up on intelligence signals.
Mitt Romney, the Republican presidential nominee, is using the attack as an example of how policy under Barack Obama has led to Middle East developments "of real concern", as he phrased it in Wednesday's first presidential debate.
Republicans in the US congress have demanded to know if the State Department failed to respond to requests for more security at the Benghazi consulate and whether there was a failure of intelligence that might have foreseen the attack.
Either way, the administration should certainly have known after the event that this was not a spontaneous attack, said Christian Whiton, a former State Department consultant under the previous Republican administration and a foreign policy adviser to Newt Gingrich during his presidential primary campaign.
The main criticism, Mr Whiton said, is that administration officials such as Susan Rice, the US UN ambassador, and Jay Carney, the White House spokesman, were "sent out in the media to basically mislead the public and they did it, because if Obama admits that it was a terrorist attack it is also an admission that his Middle East policy isn't really working".
Ms Rice denied she tried to mislead Congress. In a letter released on Friday, she wrote to three Republican senators that her comments on television news shows after the attack were based on the best information available at the time from intelligence officials.
But in the weeks leading up to November 6 election and when Mr Romney clashes with Mr Obama in their next two debates this month, the challenger is likely to adopt the line that the Obama administration misled the public.
"The president has done a pretty lousy job on foreign affairs," said Mr Whiton, describing the Benghazi attack as a "microcosm" of a faltering US Middle East policy. "I don't think Republicans should concede foreign policy to Obama … and I think it's good for Romney to talk more about this."
But others suggest criticism of the administration is politically motivated and misplaced. There are a host of challenges in securing diplomatic missions, said Wayne White, a former senior intelligence official with the State Department, including getting enough funding from congress.
Those are only exacerbated in the case of a new mission like the one in Benghazi in an unstable country where you haven't yet been able to establish a "solid intelligence apparatus", Mr White said.
"There are a lot things that critics are ignoring, because they know they can because voters don't know them," he said.
Mr White said that while an investigation was necessary and there could be "valid grievances", the rush to condemn the administration was a reflection of an "eagerness" to make it a campaign issue.
"I expect the attack to feature very heavily in the foreign policy debate between Romney and Obama," Mr White said. "Romney can leave the public with the impression of probable negligence knowing Obama will not have time to explain why this is still up in the air."
Federal Bureau of Investigation agents visited the Benghazi site of the attack this week for the first time. FBI agents are now looking to gain access to the two Tunisians held in Turkey, US officials say.