Image caption Republicans such as Congressman Darrell Issa have suggested the Obama administration engaged in a cover-up following the Benghazi attack

Official talking points about an attack on the US mission in Benghazi, Libya, were edited by the state department to remove references to terrorism, a US television network has reported.

The revelation by ABC News contradicts earlier White House comments that the memo was mostly developed by the CIA.

Four Americans, including the US envoy, died in the raid on 11 September 2012.

Republicans say the Obama administration was trying to downplay terrorism ahead of November's election.

Ambassador Christopher Stevens died of smoke inhalation when he was trapped in the burning compound, after armed men stormed the building.

Cover up claims

State department employee Sean Smith and former Navy Seals Tyrone Woods and Glen Doherty also died in the assault.

Analysis The new documents contain two rationales for the changes in language. The first is that it would prejudice the FBI investigation. Perhaps, but I am not at all persuaded. The other reason given - old-fashioned butt-guarding - is more credible. However you read the motives, the state department and apparently the White House did get the CIA to change its story. This is now very serious, and I suspect heads will roll. The White House will be on the defensive for a while.

The controversy stems in large part from an appearance on Sunday chat shows soon after the attacks by Susan Rice, the US Ambassador to the UN, who said the attack had grown out of an anti-US protest.

Other officials have said they knew at the time it was an organised, armed assault, possibly by an Islamist militant group.

According to ABC News, as the dust settled in Libya the state department offered input on the talking points memo to be distributed to Congress and to Ms Rice.

The state department wanted to remove a reference to earlier CIA warnings about terror threats in Benghazi and excise the mention of Ansar al-Sharia, a group linked to al-Qaeda, ABC News reported.

State department spokeswoman Victoria Nuland said in an email to intelligence and White House officials obtained by the ABC that the reference should be dropped because it "could be abused by members [of Congress] to beat up the state department for not paying attention to warnings", the network reports.

In November, White House press secretary Jay Carney said the information given to the public in the wake of the attack had been supplied by the intelligence community.

He said at the time: "The White House and the state department have made clear that the single adjustment that was made to those talking points by either of those two institutions were changing the word 'consulate' to 'diplomatic facility' because 'consulate' was inaccurate."

On Wednesday, a US diplomat in Libya during the attacks gave the first public account of the incident, in a Congressional hearing.

Gregory Hicks, deputy chief of mission in Tripoli, expressed frustration with the lack of military response to the incident, telling lawmakers he believed a second attack would have been deterred by a swift reaction.

'Systemic failures'

Media playback is unsupported on your device Media caption On Capitol Hill in January, Hillary Clinton angrily defended her handling of Benghazi

The Pentagon has said it could not have done anything to assist the besieged Americans.

And Mr Hicks criticised an official review of the attack, saying it focused too much on low-ranking officials.

That probe, led by former Deputy Secretary of State Thomas Pickering and Adm Mike Mullen, singled out the diplomatic security and near eastern affairs bureaus for criticism.

It said "systemic failures and leadership and management deficiencies at senior levels" in those teams led to a "security posture that was inadequate for Benghazi and grossly inadequate to deal with the attack that took place".

In congressional hearings in January, then-Secretary of State Hillary Clinton took responsibility for the security failures at the compound.

Some analysts say that Mrs Clinton, who has been cited as a possible Democratic presidential candidate in 2016, could be haunted by the incident if she chooses to run.