ZANZIBAR, Tanzania (AP) — At least 18 people were killed when a building collapsed Friday in Tanzania’s largest city, Dar es Salaam, a municipal official said Saturday, as hopes dimmed of rescuing more survivors.

Poor equipment hampered efforts to rescue more than 60 people believed to be trapped under the rubble, said a Dar es Salaam commissioner, Said Siddiq. At least 17 people, 3 seriously injured, were pulled out of the debris on Friday.

Officials said that constriction work on the building, on one of the busiest streets in Tanzania’s commercial center, was about to be completed and that the structure did not have tenants. Most of the people caught in the collapse of the 12-story building were laborers as well as those passing nearby. Some witnesses said that dozens of construction workers and food vendors were in the building when it collapsed Friday morning and that scores of children were playing soccer in a nearby playground. Others said that more than 200 casual laborers and engineers worked on the building regularly.

Mr. Siddiq said three engineers who worked on the building had been taken into custody for questioning. In recent years, building collapses have become frequent in East African countries as some property developers bypass regulations to cut costs.