Watch video from Algiers

A total of 13 United Nations staff and a number of schoolchildren were believed to be among 67 people slaughtered today in two huge car bomb attacks blamed on al-Qaeda affliated militants in the Algerian capital.

A pair of blasts occurred within minutes of each other in Algiers, the first destroying a school bus outside the Constitutional Court building and the second detonating outside United Nations High Commission for Refugees (UNHCR) in the suburb of Hydra.

A group calling itself the al-Qaeda Organization in the Islamic Maghreb has been blamed for the attacks, the deadliest so far of a series of bombings in the last few months.

The targeting of the UN will raise fears that the group is planning to internationalise its campaign and begin to target European, and in particular French, targets as Algerian terror groups did in the 1990s.

Jean Fabre, of the UN Development Programme, said that the bombing outside the UNHCR offices had killed 10 staff members. However, a total of 13 are missing after the attacks.

Massive damage was reported to UN buildings in the Hydra area after the blast.

Ban Ki-moon, the UN Secretary-General, condemned the attacks while on a trip to Indonesia, telling journalists: "This is just unacceptable. I would like to condemn it in the strongest terms. It cannot be justified in any circumstances."

Yazid Zerhouni, the Algerian Interior Minister, said that the bomb outside the UN office was likely to have been a suicide attack, while the other blast was not. They were just minutes apart. "The death toll is very high," he said.

The Interior Ministry said that the death toll stood at 22, but medical crews put the figure at 67, with scores injured.

People were seen running through the streets in panic near the Constitutional Court, and the wail of police sirens filled the air. Much of the city's central zone, containing its business and diplomatic offices, was cordoned off after the bombs.

Residents jammed telephone lines in the city of three million, attempting to reach loved ones, leaving much of the phone network out of operation.

Nicolas Sarkozy, the French President who made a state visit to Algeria last week, denounced what he described as these "barbaric, hateful and deeply cowardly acts".

David Martinon, the presidential spokesman, said: "President Sarkozy has just called President Bouteflika to express the French people’s solidarity and compassion towards the Algerian people."

Gordon Johndroe, a White House spokesman, also condemned the attack, adding: "The United States stands with the people of Algeria, as well as the United Nations, as they deal with this senseless violence."

Algeria suffered more than a decade of violence that began in 1992 when the then Army-backed government scrapped elections that a radical Islamic party was poised to win.

The violence has subsided since the 1990s, but al-Qaeda-affiliated groups have carried out a string of attacks this year, including suicide bombings in the capital in April that killed 33 people.

A further attack in September in the eastern city of Batna killed 22 people and wounded 100, shortly before a scheduled appearance by President Abdelaziz Bouteflika.

Two days later, in the town of Dellys, suicide bombers were reported to have driven a van loaded with 800km of explosives into a naval base barracks, killing 30 servicemen and wounding about 50 others.

The al-Qaeda Organization in the Islamic Maghreb, suspected to have carried out today's attack, was known during the Algerian civil war as the Salafist Group for Preaching and Combat.

It has previously declared itself committed to attack Algerian, French and US targets and overthrow the Algerian Government. In recent years, however, its attacks were confined to within Algeria.

Times Recommends

• Would you live on the wrong side of the Berlin Wall?
• Wish you were here, says Iraq tourist board
• Russian policeman’s corruption plea to Putin