In the foothills of the Caucasus mountains, a long line of broken mud cuts across the meadows. If you go anywhere near it, camouflaged guards carrying automatic weapons emerge from the forest beyond.
These guards in the Borjomi region of Georgia -- trained by US Army and SAS (British special forces) veterans -- are pawns in a new great game gripping Central Asia: their job is to protect the oil pipeline buried 3m below.
"A terrorist attack is the greatest threat we face," said the guards' commander, Lieutenant-Colonel Giorgi Pantskhava, an energetic Georgian in desert fatigues and aviator shades.
The US$4 billion BTC -- Baku Tbilisi Ceyhan -- pipeline went on stream yesterday. It is key in US plans to reduce dependency on OPEC oil producers in the turbulent Middle East. Pumping oil 1,609km from the Caspian sea to the Mediterranean through Azerbaijan, Georgia and Turkey, it will avoid Russia -- increasingly seen by the US as a resurgent superpower prepared to use control of energy resources as a political weapon.
The pipeline -- 70 percent funded by the World Bank, the European Bank for Reconstruction and Development, and export credit agencies -- took three years to build and will carry up to 1 million barrels of oil a day to Western markets. Yet its position on the faultline between Russia and its estranged former Soviet neighbors makes it a shaky bet.
The fiercely pro-Washington government of Georgian President Mikhail Saakashvili welcomed the BTC with open arms, said transit payments would help to kick-start the economy of the faltering ex-Soviet state.
Yet the pipeline, constructed and run by a BP-led consortium, has opened in the teeth of bitter opposition.
Green campaigners said the route passes too near to Georgia's Borjomi Gorge, a tourist spot with mineral water springs and abundant wildlife.
"If there is even a minor oil leak here then the reputation of the area will be irreparably damaged," said Vano Shalutashvili, of the Borjomi People's Democracy Institute, an organization that has fought for the pipeline to be diverted.
A leak on one section was detected in a test run this month.
Critics also said BTC passes too close to volatile breakaway regions in both Georgia and Azerbaijan, making it vulnerable to sabotage that could cause a catastrophic spill.
Locals are also furious with BP, claiming a host of problems from houses damaged by heavy traffic to polluted springs.