Dar es Salaam, Tanzania (CNN) -- Rescuers planned to search for survivors under a mountain of concrete and twisted metal Friday night after a high-rise building collapsed in Tanzania.

At least four people were dead and 60 were missing after the 16-story building under construction collapsed in Tanzania's largest city, government and emergency officials said.

Five children are believed to be among the missing, rescue official Walji Ali said.

The building collapsed Friday with a "huge whoosh and then thump," said eyewitness Ali Jawad Bhimani, a hotel owner who lives near the building in Dar es Salaam's normally bustling Kariakoo central business district.

"The fallen building is next to our mosque. There is a small field there where the young boys play football. The building fell right on top," he said. "But 10 to 15 of the boys playing got away safely and are unharmed."

A statement from the nearby mosque said that four of the boys believed to have been playing there were still missing.

Police and search dogs quickly flooded the scene, Bhimani said. By Friday evening, the dogs were gone, replaced by heavy equipment being used to remove debris, he said.

The Tanzanian Red Cross said rescue efforts would continue through the night. But the group also expressed relief that the casualty figures could have been far higher but the streets were relatively empty of vendors and shoppers due to a holiday.

"So far we have managed to rescue live at least 13 people and four dead bodies, two were seriously injured," Stella Marealle from the Red Cross said.

In addition to the deaths, at least 17 people were injured, said Suleiman Kova, a regional police commander.

Construction workers were among those injured, Ali said.

CNN's Sara Mazloumsaki and Brian Walker contributed to this report.