A third-floor addition under construction at a Somali mall in south Minneapolis collapsed Tuesday morning, shutting down dozens of businesses and knocking out electricity in the neighborhood.

No one was hurt at Karmel Square, where many of the shops were about to open when trusses installed only the day before at the top of the building fell down about 8:45 a.m. Approximately 25 people were evacuated from the building at 2910 Pillsbury Av. S.

Raymond Hoffner, who lives nearby, said he had already complained to the city about the project.

“It was very obvious when they started [construction] that it was very flimsy,” said Hoffner, president of the Park Square condo association across the street.

He said he was in the condo office ­Tuesday morning when the lights went out and he heard a rumble and sirens. “I was angry,” he said.

Owner Basim Sabri and City Council members involved in the area said it was an accident. The collapse involved what is to be a new floor at the mall featuring a prayer room, shops and a clinic. Construction workers were putting trusses in place late Monday to support a wall, Sabri said, and one on the end was not properly secured.

“It’s like dominoes,” Sabri said. “They fall over each other. … The wind played a big obstacle in what happened.”

The city had approved a permit for the work last month. Sabri has previously tangled with the city over starting other construction projects without approval and has often attracted controversy in his business dealings.

City records do not appear to show any outstanding code violations for construction work at the building, which is an important gathering spot for the Somali-American community and houses about 150 businesses.

But one Somali-American advocate called for a full investigation of what happened.

“Imagine, it could have happened in the middle of the evening or afternoon, when the place is packed,” said Abdirizak Bihi, director of the Somali Education and Social Advocacy Center. “A lot of people could have been hurt.’’

Crews spent hours clearing fallen debris as police blocked off Pillsbury Avenue. One shopkeeper lamented that the beef, chicken and goat meat at his restaurant was going bad.

“It’s going to spoil the food,” said Mohamud Isse, owner of Uruba Cafe. “They’re not letting anyone in.”

Sabri said late Tuesday that businesses were free to open as usual Wednesday morning, because Xcel Energy was turning the lights back on and authorities had finished inspections. Though he is often full of colorful criticisms of City Hall, Sabri said city staff was “very, very helpful” following the incident.

“For real,” he said. “I’m not being sarcastic.”

-- Staff writer Tim Harlow contributed to this report.