ALGIERS, Algeria - A pair of suicide bombings that killed at least 24 people in this capital city yesterday have raised the specter of a coordinated offensive by al-Qaeda-linked groups against North Africa’s governments and their Western allies, particularly in Europe, according to intelligence officials.

The attacks, which struck a building housing the prime minister’s office, as well as a police station, were the first major bombings in several years in the once war-torn Algerian capital. They came amid a recent rise in Islamic extremist activity in the North African region known as the Magreb, including bombings in neighboring Morocco.

Responsibility for the bombings was claimed by al-Qaeda in the Islamic Magreb, an Islamist group that has pledged loyalty to Osama bin Laden.

“With a suicide attack in the heart of Algiers, you have an escalation to a new level,” said Jean-Louis Bruguiere, France’s top antiterror magistrate. “It’s unquestionably an attempt at destabilization and a sign of the emergence of al-Qaeda in the Magreb as an organization.”

In Washington, U.S. officials said the attacks were part of a spate of incidents that showed a sharp and troubling escalation of extremist activity in the region.

“When there is an attempt made with the prime minister as the likely target, of course it is significant,” said one U.S. counterterrorism official. “But I don’t want to overstretch it and say that these things came out of the blue. There is a context of militancy [in Algeria], and the government is plainly aware of it and has taken steps against it.”

One of the suicide bombs, driven by a man in a Renault sedan, targeted the primary entrance to the main government building in Algiers, an office tower called the Government Palace. It killed at least 12 people and wounded 135, according to the nation’s official news agency.

The blast incinerated bodies, shattered panes of glass, and sent a huge plume of black smoke into the sky.

“We had arrived among the first, to help the casualties,” said a resident of the district, who is 30 and gave only his first name, Yacine. “I saw several burnt cars and three bodies of women blackened by the flames.”

Harried rescue workers carried off victims covered in blood. Ambulances sped to and from hospitals, and sirens screamed throughout the city. Rumors of further bombings spread as panicked residents fled from a scene that evoked dark memories of Algeria’s brutal 1990s civil war.

Arabic news channels showed footage of weeping residents crowded in front of a government office seeking information about loved ones.

“They are criminals who want to sabotage the country!” a young woman in front of the hospital shouted angrily. “May God Almighty punish them and send them to hell.”

The other bombing struck at a police station east of the capital in the suburb of Bab Ezzouar, killing at least 12 and wounding 87, said the Algierie Presse Service, citing civil-defense officials.

Al-Jazeera television said a caller phoned the network to claim responsibility for the near-simultaneous attacks on behalf of al-Qaeda in the Islamic Magreb. The network also reported that the group had posted Web messages taking responsibility for the attacks, and photos of the three extremists who carried out the bombings. Two wore green scarves over their faces.

The caller to Al-Jazeera, who identified himself as Abu Mohammad Salah, said that 1,500 pounds of explosives were used in the downtown Algiers bombing.

He vowed that al-Qaeda would continue its operations “to liberate every acre of the lands of Islam . . . and liberate our men in prisons in Tunisia and Algeria,” Al-Jazeera reported.

Prime Minister Abdelaziz Belkhadem, unhurt in the attack, called it “a criminal and coward act perpetrated at the time when the Algerian people are seeking national reconciliation,” according to the news agency.

The oil-rich country is preparing for May 17 parliamentary elections meant to push the country toward peace. In 1992, the army canceled elections that Islamist activists were poised to win, setting off a civil war that left more than 150,000 dead. The violence has tapered off in recent years, despite occasional bombings and assassinations.

All but one extremist group, the Salafist Group for Preaching and Combat, remained. Last year, it swore allegiance to al-Qaeda.

The Algiers government recently launched attacks on the group’s suspected eastern Algerian strongholds near Kabylia. The Interior Ministry, which includes the counterterrorism unit that launched the recent attacks, is inside the Government Palace that was targeted yesterday.

By Arezki Ait-Larbi and Borzou Daragahi Los Angeles Times