Moroccan investigators have not uncovered links between bombings one day apart in Morocco and in Algeria, but "we don't rule it out," said Interior Minister Chakib Benmoussa on Wednesday.
At a news conference, he said three Moroccans who blew themselves up Tuesday had relatively small amounts of explosives that they wore on their bodies, while the Algerian bombings on Wednesday involved cars packed with explosives.
Benmoussa said the timing of the attacks was possibly coincidental. He pointed out that the Morocco bombings were provoked when the police closed in on the men, and apparently not planned.
"We don't rule it out, but we have established no link," he said.
The explosions in Casablanca's Hay al-Farah neighborhood killed a policeman and injured 21 other people, Benmoussa said.
On Tuesday morning, police acting on an informant's tip cornered four suspects with alleged ties to Abdelfattah Raydi, who blew himself up at a Casablanca cybercafe last month, killing himself and injuring four, said Benmoussa.
Police shot Mohamed Mantala when he emerged from the apartment the four shared and tried to detonate explosives, said Benmoussa.
Suspect Mohamed Rachidi fled to the building's roof and set off his bombs. Ayyoub Raydi, brother of Abdelfattah Raydi, and Said Belouad -- who was identified Wednesday by the state news agency -- blew themselves up in the street later Tuesday after police flushed them out of the building.
Police found bomb-making equipment and knives in the apartment, said Benmoussa. He added that the men who killed themselves Tuesday had the same detonators on their explosive belts as Abdelfattah Raydi, who blew himself up at the cybercafe.
The suspects had taken up the habit of wearing their explosives whenever they left their apartment, wanting be ready at all times to blow themselves up if caught by authorities, said an Interior Ministry official. He asked not to be named because of ministry policy.
Moroccans are often pious, yet pride themselves on acceptance of other religions. But an austere, sometimes violent strain of Islam has taken hold in the country in recent decades.
The violence offered a reminder of suicide bombings in 2003 that killed 45 and launched a campaign against extremism, waged by police in the streets and imams in Morocco's state-controlled mosques.
Thousands of suspected terrorists have been arrested since 2003. Authorities are currently seeking 15 suspects in Morocco and abroad, in the sub-Saharan Sahel region, said the Interior Ministry official.
Abdelfattah Raydi's group is equally international, said Mohamed Darif, an expert on Islamic terrorism at Mohammedia University.
"This is a terrorism without borders, made of multiple cells who don't even always know one another," Darif said. That, plus Al Qaeda's effort to expand its influence into North Africa, points to "organizational links between (Raydi's group) and groups outside Morocco," he said.
Police have arrested 31 people in connection with the March 11 Internet cafe bombing and are seeking three others, the Interior Ministry official said. Authorities say the group was planning a series of attacks on Casablanca's police stations, port and tourist sites around Morocco.
Tuesday's explosions come ahead of parliamentary elections in September, which the Islamist Justice and Development Party, known as the PJD, is expected to win.
The rise in violence and extremism will likely strengthen the PJD's position, according to Mohamed Tozy, a politics professor at Casablanca's Hassan II University.
Moderate Islamists who renounce violence like the PJD "are the allies of North African regimes, the best protection against violent Islamism," Tozy said.
Islamic violence has recently rekindled across North Africa, where tough security measures and a series of amnesties for repentant militants in Algeria have failed to quench the flames.
Ultimately, North African regimes must win over their populations through economic and democratic reform, thus robbing extremists of popular support, said Darif. "After all, most North Africans don't support this culture of death."