The two bombers detonated their explosives in the middle of a boulevard that runs behind the cultural center, killing themselves and wounding a woman, the official said on condition of anonymity, citing ministry policy.
The American Consulate and a synagogue are also both in the neighborhood. The three suspects were arrested at the scene, the official said.
The official identified one of the dead bombers as Mohamed Maha, born in Casablanca in 1975. He was not previously known to police, the official said.
On Tuesday, three suicide bombers also blew themselves up in Casablanca, Morocco's largest city and economic capital, after being cornered by police. A police sniper shot and killed a fourth man who authorities said appeared to be preparing to detonate explosives.
The Interior Ministry official said the two bombers on Saturday were not being pursued by police when they detonated their explosives.
The attacks stoked new fears of terrorism in this North African kingdom and across the region. On Wednesday, 33 people were killed and more than 200 were injured in al Qaeda-claimed suicide car bombings in neighboring Algeria that targeted the prime minister's office and a police station.
The U.S. Embassy warned of possible new attacks in the Algerian capital on Saturday. In a statement, it said attacks could strike near the Algiers central post office and the ENTV national television headquarters. It did not cite a source for its information.
Algerian authorities have identified one of Wednesday's three reported suicide bombers who drove the cars laden with explosives, state radio and television reported. The media, citing authorities, described him as a youth from a poor Algiers neighborhood but did not name him.
The French-language daily Liberte identified the bomber as 23-year-old Bilal Oudina, who has been jailed three times for crimes linked to drug trafficking. It did not cite sources for its information. The paper said he began to pray and frequent Islamist circles six months ago and disappeared from his neighborhood three months ago.
Al Qaeda in Islamic North Africa claimed responsibility for the Algeria attacks. The group formerly went by the name of the Salafist Group for Call and Combat, or GSPC, but officially linked with al Qaeda at the start of the year. It was built on the foundations of the Algerian insurgency that has fought since 1992 to try to topple the nation's secular government. The GSPC has refused an official amnesty that drew other armed insurgents home.
The new al Qaeda wing posted pictures, names and details about the bombers on an Islamic Web site known as a clearing house for extremist groups' material. The site said the man who attacked the prime minister's office, identified as Mouaz bin Jabl, used 1,500 pounds of explosives. The claim could not be immediately confirmed.
Moroccan Interior Minister Chakib Benmoussa said on Wednesday that police were still seeking three or four members of Tuesday's group in Casablanca.
Last month, a suicide attack at a cybercafe in the city killed the bomber and injured four others.
The Muslim kingdom of Morocco has long been known for its stability despite the violence in neighboring Algeria. But in May 2003, five suicide bombings around Casablanca killed 45 people, including a dozen bombers.
Authorities launched an unprecedented crackdown on suspected militants, arresting thousands of people, including some accused of working with al Qaeda and its affiliates to plot attacks in Morocco and abroad.