A Venezuelan military helicopter has violated Colombian airspace and spied on military facilities in the northwest of the country, the Colombian Foreign Ministry said.

"The incident took place early on Wednesday. A Venezuelan Bell helicopter flew near an army base hosting a [Colombian] infantry brigade in the outskirts of the town of Arauca," the ministry said in statement.

"These actions are unacceptable," the ministry said, adding that an official letter of complaint would be sent to Caracas asking for an explanation.

Ties between Venezuela and Colombia deteriorated last August after Washington signed a deal with Bogota allowing U.S. forces to run anti-drug operations from seven Colombian military bases.

Venezuelan leftist President Hugo Chavez has criticized the deal as a threat to his country and called for the Venezuelan people and army to prepare for a war.

He has also accused Colombia and the U.S. of sending spy drones over the border with Venezuela and ordered his military to shoot them down on sight.

Source: RiaNovosti