In Colombia, the left-wing guerrillas are turning to new targets, including oil to squeeze the government. The country's second-largest oil field, operated by the U.S. company Occidental Oil, has long been a target for sabotage.

But this year, guerrilla attacks on the pipeline have become ferocious, choking off the local economy, poisoning the environment, and causing a huge drain on the military.

The morning begins with helicopters, bringing a handful of Occidental Oil executives and visitors to the company's base camp on Colombia's eastern plains.

After a baggage search by Colombian soldiers, a heavy metal turnstile allows you into Occidental's spacious compound. Overhead, a phantom jet, equipped with infrared surveillance, cruises the blue sky - part of the Occidental security team.

Larry Meriage is spokesman for Occidental. He admits pumping oil in Colombia is a serious security challenge. "We really are an island surrounded by a sea of guerrillas," he said. "The guerrillas control the highways. It would be very dangerous for our people to be moving around on the roads, particularly, if you have senior staff coming in from Bogota. So, we use helicopters."

The main threat to production at the Cano Limon oil field this year is really down the pipeline that carries the oil from the plains to the Caribbean coast.

Forty kilometers from the Occidental camp, potholes of petroleum are still sizzling, two days after rebels blew a hole in the pipeline. This was pipeline attack number 162, this year.

A swath of land the size of three football fields has been scorched to a deep fried black. At the center, a huge bonfire spews black billows of smoke into the air.

Two dozen soldiers walk cautiously around the burn site, alert to a possible follow-up ambush or hidden landmines left behind by the rebels. The guerrillas have attacked the pipeline so frequently this year, the Cano-Limon oil field has been paralyzed more than half the year.

Captain Carlos Castro, leader of the mobile army unit guarding the site, explains that the day before, in the nearby town of Saravena, it rained oil.

People looked at their clothes and realized it was raining black drops, said Castro. The smoke from a pipeline attack had gathered in the clouds and came down in the rain. More than 300,000 barrels of oil have spilled this year, most of it into lush wetlands - the habitat of hundreds of species of birds and reptiles.

But the rebel attacks are so frequent, the state oil company Ecopetrol has stopped trying to clean it up. Mr. Meriage explains. "Because of the more aggressive tactics of the guerillas now," he said, "it is not safe for the crews to remain in the areas, so basically there has been a policy decision made by Ecopetrol under those circumstances. They simply allow nature to take its course."

In past years, the rebels behind the attacks were usually members of the ELN - the smaller of Colombia's two left-wing guerrilla groups. They blew up the pipeline as a statement, rebel leaders said, against what they considered greedy profiteering by Occidental. But more than anything, the attacks gave the ELN publicity.

And they usually spaced out their attacks, so they rarely affected production or oil royalties. In the towns around here, everyone lives off oil royalties, including the ELN.

According to Colombian oil consultant Robert Stewart, the ELN demand a cut from every business. He said, "Even from the distribution of beer to Coca-Cola. Bus contractors, boat operators, virtually everybody is extorted."

But this year, the dynamite changed hands. Now, the country's larger, most aggressive rebel group, the FARC, has taken over the attacks with such ferocity, production and royalties have petered out. The region is gasping. Some believe the FARC's trying to starve out the ELN and take over the region.

But Mr. Meriage believes their main target is the Colombian government. After all, oil is Colombia's number one export. He said, "The loss to Colombia this year if you look at royalty payments, the share of production is approaching half a billion dollars. So if you're the guerrillas, and one of your objectives is to undermine the authority of the government and weaken it economically, by attacking the oil infrastructure, you do that."

The attacks are now drawing the wrath of the U.S. government. The U.S. Ambassador to Colombia, Anne Patterson, recently announced the U.S. will offer Colombia's public forces training to protect the pipeline. Since September 11, Mrs. Patterson has taken a harder line with the Colombian rebels, comparing them to al-Qaida terrorists.

Officials at Occidental are hopeful it may be a sign that Washington may step in to give more direct support to the Colombian army, especially where economic interests are at stake.