The Moroccan Government says it has identified eight of the suicide bombers who carried out Friday night's attacks in Casablanca.
The majority of those killed and injured were local Moroccans
Justice Minister Mohammed Bouzoubaa told Moroccan television that the authorities had obtained their "names, families and affiliations" from an accomplice who did not die in the bombings.
But he conceded: "We still do not know the names of the others."
Police have been rounding up militant Islamists in Casablanca in connection with the attacks.
At least 30 people were arrested in a major security operation across the city.
Mr Bouzoubaa said some of the attackers were "Moroccan citizens who came to the country a long time ago".
"They came from abroad," he said.
King Mohammed VI went to Casablanca on Sunday and toured the sites targeted by the blasts, starting with the Hotel Safir.
The king has called for a full and transparent investigation into the attacks.
And he has pledged to cover the medical costs of the wounded.
A focus of the inquiries will be on whether the attackers had links with any local Islamic organisation, he says.
At least 41 people were killed and about 100 injured in the five blasts that hit Casablanca within 30 minutes of each other.
The targets included a Jewish community centre, a busy Spanish restaurant and social club, and the Belgian consulate.
The explosions came amid worldwide terror alerts and just four days after a co-ordinated series of bombings in the Saudi Arabian capital, Riyadh, killed 34 people.
Morocco's Interior Minister Mustapha Sahel said there were similarities between the bombings in Casablanca and Riyadh.
A team of French forensic experts are to join Moroccan investigators
The BBC's security correspondent Frank Gardner says there are indications that the Casablanca blasts were probably the work of a "North African cell linked to al-Qaeda".
In the past, Osama Bin Laden's terror network has carried out similar co-ordinated suicide bombings against Western or Jewish targets.
But this was the first such devastating attack in Morocco - a staunch US ally which nevertheless opposed the war on Iraq.
The bombings drew widespread international condemnation. France and the United States have offered to help find those responsible.
The authorities have deployed extra police and soldiers across the city - especially outside hotels and restaurants - and set up checkpoints.
But correspondents say local people are angry that not enough was done to prevent the bombings in the first place, accusing the government of complacency.