Suspected Al Qaeda militants killed 12 Mauritanian soldiers Monday, two senior officials said. The attack, which came after the terror group promised to avenge the country's recent coup, was the worst suffered by the military in three years.

Assailants ambushed an army unit patrolling the desert in Tourine, about 530 miles north of Nouakchott, a lieutenant-colonel told The Associated Press. The same account also was given by a senior official in the presidency. Both officials spoke on condition of anonymity because they are not authorized to speak to the media.

Al Qaeda in Islamic North Africa had called for a holy war to avenge the Aug. 6 overthrow by the military of President Sidi Ould Cheikh Abdallahi, Mauritania's first freely elected president.

Monday's attack marked the highest death toll incurred against the army in a single attack since 2005, when fighters linked to Algeria's former Salafist Group for Call and Combat killed 15 soldiers in an assault on a desert outpost in Mgheiti, which is in the same area near Mauritania's borders with Mali and Algeria.

The Group for Call and Combat later recast itself as a branch of Usama bin Laden's Al Qaeda network operating in northern Africa.

The United States had sent dozens of troops to train Mauritania's military in the far northern deserts, hoping the country could act as a bulwark against the southward encroachment of Al Qaeda-linked militants in North Africa. But the U.S. suspended those programs along with more than $20 million in aid after the August coup.

In late 2007, gunmen believed linked to Al Qaeda murdered four French tourists, prompting organizers of the famous Dakar Rally to cancel the race this year. Mauritanian authorities say suspected Islamist terrorists have fired shots at the Israeli Embassy in Nouakchott and killed three soldiers near the town of Ghallawiya, around 430 miles north of the capital.

The coup leader, Gen. Mohamed Ould Abdel Aziz, has accused Abdallahi of being soft on terrorism and freeing radical Muslims from jail who had been implicated in plotting attacks on Western embassies. He also has criticized Abdallahi for allotting Cabinet posts to "Islamic extremists" from the Tawassoul party, which represents hard-line Muslims. The party claims it is wrongly branded as hard-liners.