Mexican Interior Minister Juan Camilo Mourino died with seven others in a small plane crash in Mexico City Tuesday, President Felipe Calderon said, paying homage to a friend and colleague.

The 37-year-old minister `was one of my closest collaborators and one of my best and closest friends,` Calderon said in a brief statement to journalists.

The government `will carry out all necessary investigations to find out the causes of the tragedy,` Calderon added.

The executive jet of the interior ministry crashed at 6:40 pm (0040 GMT) on a pedestrian street near the capital`s main Reforma avenue during rush hour traffic.

Mexican government security advisor Jose Luis Santiago Vasconcelos, other senior officials, the pilot and co-pilot, were also killed, reports said.

Some 40 people were injured in the crash, which caused a large explosion and burned some 30 vehicles.

The city`s mayor, Marcelo Ebrard, said five seriously injured people had been transferred to hospitals and that a fire set off by the accident was under control.

`The explosion was enormous, the flames rose higher than the buildings on Reforma,` a witness told AFP.

The cause of the accident was unclear, although experts at the crash site said it was unlikely the plane had been attacked.