A man was arrested when a grenade was found in his carry-on luggage as he tried to board a commercial flight in the southwestern Colombian city of Guapi, authorities said.

The incident remains under investigation, police sources told Efe.

Authorities have yet to determine whether the suspect is part of an armed group, where he obtained the grenade or what he intended to do with it, the sources said.

The man was trying to board a flight to Cali, Colombia's third-largest city, Caracol Television said.

Guapi is located on the Pacific coast at the mouth of the Guapi River. The city is six hours by boat from Buenaventura, the country's leading Pacific port.

Leftist guerrillas, right-wing militias and drug gangs operate in the area around Guapi. EFE