DAR ES SALAAM (Reuters) - Rescue workers have pulled 29 bodies from the rubble of a collapsed building in Tanzania's commercial capital Dar es Salaam, a senior official said on Sunday.

The building of more than 12 storeys, which had been under construction near a mosque in the Kariakoo district around the city center, caved in on Friday morning. Several cars were crushed and boys playing soccer nearby were among the dead.

"We have now recovered a total of 29 bodies from the rubble of the collapsed building," Dar es Salaam Regional Commissioner Said Meck Sadick told Reuters.

He said workers were now reaching the basement where there was a store for equipment and more bodies might be found. He said digging would continue until all bodies were recovered.

Tanzania's buoyant economy has fuelled a building boom, especially in Kariakoo and the city center. But the speed of construction has raised concerns about safety standards.

President Jakaya Kikwete, who visited the scene on Friday, ordered authorities to act against responsible parties. Police said four people had been arrested over the incident.

(Reporting by Fumbuka Ng'wanakilala; Writing by Edmund Blair; Editing by Mark Heinrich)