CASABLANCA (AFP) -- As Casablancans headed back to work in Morocco's economic capital on Monday many questioned why two brothers at the weekend blew themselves up near the U.S. consulate here but avoided killing any bystanders in the attack.

"I'm worried without really being (worried). I'm a little afraid because the suicide bombers don't have clear targets, but at the same time I feel reassured because they didn't want to kill anyone.

They wanted to spare the civilian population," 28-year-old teacher Inane Haidar told AFP after dropping her two children off at the Italian school near the U.S. consulate.

At 9:05 A.M. (GMT) on Saturday, bomber Mohamed Maha, 32, set off explosives 40 meters (150 feet) from the heavily guarded entrance to the U.S. consular building in the upscale Casablanca neighborhood of Gauthier.

After the explosion, his younger brother Omar ran off along the Boulevard Moulay Youssef towards the American Language Center, a private school, where he blew himself up, just 150 meters from the first attack.

The two brothers were described by shocked residents in the working-class Casablancan suburb where they lived as mild-mannered and quiet. They did not wear beards and police had not suspected them of being Islamic extremists.

"They don't have the profile of bearded Islamists and one cannot say they were from al Qaeda, since that organization does not respect human life," Haidar said.

Loubna Benani, the 25-year-old owner of a real estate agency in the neighborhood, said the motive for the attack was confusing. "They didn't want to kill either civilians or police, because Saturday morning it is rather deserted (here). They could have found other much more crowded areas or have come another day. What they wanted is a mystery."

A police official meanwhile said Saturday's incident was "a desperate act in response to the successful crackdown in recent weeks by the police and security services to dismantle terrorist cells".

The police crackdown was intensified last week when five suicide bombers killed themselves in the port city in as many days.

Those attacks, together with the recent coordinated suicide bomb attacks in the Algerian capital Algiers, have fueled fears of increased militant strikes across North Africa.

Mohamed Darif, a professor at the Mohammedia University, insisted Saturday's fraternal bombers had clearly targeted U.S. interests.

"These suicide bombers did not blow themselves up in a place full of civilians but in a not very busy area near the United States general consulate," he told AFP. The owner of the Beverly cafe, next door to the consulate, meanwhile said he thought the bombers "wanted to create a feeling of danger but without wanting to kill people."

In support of his case he said he had heard that one of the men had told a security guard at the American Language Center that "I could kill you but I won't," before moving away and setting off his explosives.

The 44-year-old cafe owner, who did not want to give his name, pointed out that there is always a long line of applicants for United States visas outside the consulate during the week. "Just imagine the massacre they could have committed," he said.

That the recent Moroccan attacks happened in Casablanca, the scene of extreme contrasts between rich and poor and between flamboyant modernism and religious conservatism, is not surprising, according to one man.

"I just hope that these acts will incite the state to ask itself what the reasons could be that pushed these people toward death. It is desperation and poverty," a foundry technician who identified himself only as Mohamed said.

"I have already been in the huge slum of Sidi Moumen (where most of the suicide bombers in recent weeks came from). Its inhabitants are dead people and so it is easy to turn them into human bombs," he said.