WASHINGTON — A US military investigation has recommended disciplinary action for up to seven troops over their role in the burning of Korans at a base in Afghanistan, a US official said Tuesday.

No final decision has been made yet on the findings of a probe that examined the torching of Korans at a US air base in February that sparked deadly riots, said the official, who spoke on condition of anonymity.

The investigation called for administrative punishment but no criminal charges of up to six Army troops and one member of the Navy, the official told AFP.

The US Army confirmed the probe of the incident had been wrapped up but offered no details on recommended disciplinary measures.

"The investigation is complete and is pending review," said spokesman George Wright.

The Koran burning ignited days of violent anti-US protests in which about 40 people died, plunging relations between foreign forces and their Afghan allies to an all-time low and forcing US President Barack Obama to apologize.

Taliban insurgents sought to exploit the incident and called on Afghans to kill foreign troops in revenge.

The Taliban claimed to have been behind the shooting deaths of two US advisers who were killed inside the Afghan interior ministry after the incident.

Top US commanders issued numerous apologies over the Koran and insisted it was an accident, but details of exactly how the incident occurred have remained unclear pending the outcome of the probe.

Of the troops who might be penalized, it was unclear how many were officers and how many were enlisted personnel.

After the incident, some US officials said privately the military had removed Korans from the US-run prison at Bagram because inmates were suspected of using the holy book to pass messages to each other.

But the account has yet to be officially confirmed.

US officials say relations with Kabul have been shored up since the incident and the two governments have signed a partnership agreement opening the door to a long-term American military presence after 2014, when the bulk of US and NATO combat forces are due to withdraw.

Afghanistan is a deeply religious country where slights against Islam have frequently provoked violent protests and Afghans were incensed that any Western troops could be so insensitive, 10 years after the 2001 US-led campaign that toppled the Taliban.

A radical Christian pastor in the US state of Florida sparked protests in Afghanistan and elsewhere in the Islamic world when he threatened in 2010 to burn a copy of the Koran on the anniversary of the September 11 attacks on New York and Washington.

The pastor, Terry Jones, went ahead and burned a copy of the sacred book in March 2011.

In May 2008, thousands protested in Afghanistan over the desecration of the Koran by an American soldier in Iraq who used a copy of the Muslim holy book as a shooting target.