A Petroecuador official said an explosion that halted crude transport in Ecuador's main crude oil pipeline for 32 hours from Saturday night was caused by an "external problem," which a local government official said was probably dynamite.

The Trans-Ecuadorean crude pipeline began pumping again at 8:55am local time yesterday after an explosion late Saturday destroyed 13.5 metres of the tube, spilling 3,635 barrels of crude and halting all activity.

While state-owned Petroecuador would not confirm the origin of the explosion, a spokesman for the oil company told Reuters "someone did something. Who, we don't know." Victor Velasco, governor of Sucumbios province where the rupture occurred, said the "earth shook" when the pipeline burst, and that technicians repairing the duct had since found evidence of explosives.

"According to the sergeant in charge of the pipeline, it was a dynamite attack," Velasco told Reuters. The explosion, which occurred near pumping station Lumbaqui in the Amazon jungle region, did not affect Ecuador's oil exports since the country boasts sufficient stock to cover losses in emergency situations, Petroecuador said in a statement.

According to an oil industry source, some 1,200 barrels of crude were spilled into the Aguarico River, about 50 kilometres south of the nation's border with Colombia. A statement from Petroecuador said the environmental damage was "minimal."

This is the seventh time the pipeline has been paralyzed so far this year. The duct, which stretches 498 kilometres from the oil-rich Amazon jungle region to a refinery on the coast, can transport up to 380,000 barrels of crude daily.

Ecuador, the fourth-biggest exporter and sixth-largest producer of crude in Latin America, is currently negotiating the construction of a second pipeline for heavy crude, due to begin in 2001. The Andean nation's biggest export - oil - funds nearly 40 percent of the government's budget.

In recent months violence in Sucumbios province has increased, with authorities speculating that increased tensions among guerrilla and paramilitary forces in nearby Colombia could have repercussions in Ecuador.