A four-alarm fire at a midtown strip mall destroyed four business units in the mall, a fire official said.

The Tucson Fire Department called out the extra alarms to battle the blaze at the 29th Street Business Plaza, which is across the street from Freedom Park near South Swan Road.

The fire broke out at about 3 p.m., said Tucson Fire Capt. Barrett Baker. The fire was brought under control shortly after 5 p.m.

He said when units arrived heavy smoke was visible from two businesses in the strip mall.

The fire sent thick plumes of smoke into the air that could be seen from across Tucson.

Baker said the fire destroyed four business spaces at the mall. The roof caved in on the four units. It wasn't immediately known if all four units were occupied by businesses.

Firefighters managed to save about 20 units. The cause of the fire and a damage estimate were not immediately available.

Tucson police shut down the eastbound and westbound lanes on 29th between Swan and Rosemont Avenue. The street is expected to be closed through Monday night.

Veronica Salvador, who lives in a home behind the mall, said she saw firefighters on the roof of the building cutting holes to access the fire. They began using an aerial ladder to spray water onto the burning building.