Suicide bombers cut the throat of the porter as they charged into an exclusive Spanish club in Casablanca.
A policeman at the Casa de Espana said the attackers slit the porter's throat on entering the club, which has a large inner garden popular with Spanish businessmen and diplomats.
It had been a long holiday weekend and Moroccans were still celebrating last week's birth of King Mohammed's son and heir.
Officials said at least 24 people - including about 10 bombers - died and 60 were wounded in a series of attacks across the country's largest city and commercial capital.
Casa de Espana club president Rafael Bermudez, still in shock and wearing a blood-stained shirt, told Reuters: "I heard two blasts and thought they were short-circuits."
Witnesses said at least one attacker blew himself up with grenades strapped to his belt.
It was not immediately known how many died at the club, although witnesses believed it suffered the highest toll. Rescue workers left the building carrying black plastic bags which appeared to contain parts of dismembered bodies.
In another part of the city, residents said a bomber blew up himself and three young men passing-by about 100 metres (yards) from the main gate of the old Jewish cemetery in a populous district.
Residents said the bomb appeared to have been a home-made device packed with nails.
At Ibnou Roch hospital, families gathered outside the emergency unit seeking information about wounded relatives.
Two women wailed over the loss of their brother. "God, why did you take Abdelatif? He just got married," one of the two sisters cried.
A Jewish community centre was also targeted. A police officer said the attack again appeared to have been carried out by bombers wearing explosives around their belts.
The one-storey building was badly damaged, with blood stains visible five metres (16 feet) up its facade. Broken glass, bricks and rubble littered the street where a car was burned out in front of the building.
It was not known how many casualties there were.
The five-storey Belgian consulate was also badly damaged opposite a Jewish-owned Italian restaurant. The U.S. consulate is situated nearby, but a State Department official in Washington said no U.S. government facility was hit.