LISBON, Portugal (AP) _ Panic, not gas, killed seven people in a crowded Lisbon nightclub where two canisters of gas were set off over the weekend, police said Monday.

At least 500 people were at the Luanda club during the attack at 4:30 a.m. Sunday. The lights went out at the same time, prompting a blind stampede to escape the fumes.

``The causes of death are generally attributed to situations of panic,'' a police statement said.

The statement said 35 were injured.

Police, who earlier speculated the canisters contained pepper gas, said they will be analyzed to identify the contents.

Investigating inspector Joao de Sousa said a number of suspects had been identified, but none has been questioned and no arrest warrants were issued.

He said police had finished collecting evidence at the club, a popular hangout for immigrants from Portugal's former African colonies in the busy riverside area of Alcantara.

Police have declined to speculate on a motive for the attack. The electricity appears to have been deliberately cut off simultaneously with the gas attack.

The dead included a Spanish woman and six Angolans, most in their 20s.

The Spanish woman, Ester Lopez, 20, had come to the Portuguese capital with two friends to visit a third living here, the Spanish consulate said.

She will be cremated in Lisbon and her ashes will be taken back to Madrid, according to her parents' wishes.

``They were very affected by this. She was an only daughter,'' the consulate's Maria Vitoria Azpiazu said at the morgue.

Another victim, Antonio Campos, 30, from Angola, had gone to the club for the first time Saturday with friends.

``Now they have to find the criminals,'' his brother Adao said after identifying the body.

A club employee, who asked not to be identified, said there was fierce competition for business among clubs in the area.

The attack shocked Portugal, which maintains strong ties with its former African colonies and is home to a large African population.

Flowers were laid on the club's doorstep Monday and a small photo of one of the victims was pasted on the front door.