An explosion went off Sunday at an airport in Kenya's (search) capital, wounding at least two people Sunday and prompting authorities to seal off the facility to air traffic, witnesses said.

Pilots monitoring communications over short wave radio said emergency personnel indicated the blast at Wilson Airport (search) was caused by mishandling of explosive chemicals or a gas canister.

Police spokesman Superintendent Jaspher Ombati said that he received reports of an explosion at the airport and was trying to get more details.

At least two people were evacuated by ambulance from the airport, witnesses said, speaking on condition of anonymity.

A reporter with The Associated Press saw fire fighters at the scene, with part of the roof at the departure lounge destroyed by the explosion.

Both the Kenya Civil Aviation Authority and Kenya Airports Authority refused to comment.

The airport is one of the busiest in Kenya's capital, Nairobi (search), serving as a hub for tourist and cargo charter flights. The airport is used mostly by helicopters and light- and medium-sized aircraft.