Bogota, Jun 23 (IANS/EFE): Four of the 15 soldiers on board a Colombian army Black Hawk helicopter were killed in an explosion after it landed in a minefield, military officials said on Tuesday.

The accident occurred at Teorama municipality in Norte de Santander province.

According to reports from the soldiers on board the transport helicopter, six of whom were wounded, the explosives at the landing site were placed and detonated by guerrillas with the Revolutionary Armed Forces of Colombia (FARC), the Defense Ministry said in a communique, revising initial information that the chopper had been shot down by the rebels.

"The information we have is that the incident occurred on the Santa Lucia trail near the small town of El Aserrio in the Catatumbo region," Teorama prosecutor Ever Pallares told EFE.

The helicopter belonged to the army's 33rd Mobile Brigade, local media reported.

The helicopter was apparently headed for the Filo Guamo area, where technicians of state oil company Ecopetrol are working to repair a stretch of the Caño Limon-Coveñas pipeline, damaged the week before in a guerrilla attack.

Operating in that area bordering on Venezuela are guerrillas of the FARC, the National Liberation Army (ELN), and the Popular Liberation Army (EPL), which authorities say is chiefly engaged in drug trafficking.