MOSCOW – Washington scored a significant victory yesterday in its contest with Moscow for influence in Central Asia when Kazakhstan agreed to start pumping oil to the West through a British Petroleum pipeline that bypasses Russia and Iran.

The deal, secured largely because of a personal visit to Kazakhstan last month by Vice President Cheney, will infuriate the Kremlin.

But there will be secret relief in European capitals, where there is growing concern over Russia’s apparent willingness to use its vast energy supplies as a political weapon.

The Kazakh president, Nursultan Nazarbayev, told an investors’ conference in the capital, Almaty, that a formal agreement would be signed next week to begin delivery through an existing BP pipeline that connects Azerbaijan to the Turkish coast.

This loops through Georgia, thus avoiding Russia to the north and Iran to the south.

The deal will give the West greater access to the vast oil fields of the Caspian Sea – estimated to hold the world’s third-largest reserves – and ease its growing dependence on energy from Russia and the Middle East.

America and Russia are locked in fierce competition for access to Central Asia’s vast energy wealth.

Russia has emerged as the world’s second largest oil producer after Saudi Arabia, a fact that has allowed the Kremlin to recover some of its Cold War swagger.

Mr. Cheney, a former oilman who for more than 20 years has highlighted the importance of the Caspian Sea, has grown increasingly skeptical of Russia’s intentions toward the West.

He launched a scathing attack on the Kremlin last month and caused outrage by flying to Kazakhstan immediately afterward, where he was fulsome in his praise for Mr. Nazarbayev’s even more democratically dubious regime.

President Aliyev of Azerbaijan, the other major oil-producing country on the Caspian to sign an energy deal with the West, was recently entertained at the White House – though he too has been accused of cheating in an election last year.

The new deal could help to bring down world oil prices, another factor likely to upset Russia, whose energy-dependent economy could wobble if crude falls below $50 a barrel.

Kazakhstan has become a serious rival to Russia as a hydrocarbon exporter. But Mr. Nazarbayev is in a tricky situation. The financial benefits of an American deal may be tempting but must be set against his country’s geographical vulnerability to its powerful neighbors Russia and China, neither of whom is keen on his flirtation with the West.