Gazprom has delayed selecting its partner for the Shtokman field

The news comes as Russia is selecting foreign firms to help Gazprom develop the Shtokman gas field, in the Arctic.

"If you discriminate against us in the WTO, you can't expect us to welcome you with open arms," the Kremlin said, reported Dow Jones.

Earlier, Russia said the $20bn (�10bn) gas project would be further delayed.

Reciprocity

However the Kremlin's spokesperson, Dmitry Peskov rejected the notion that Russia was drawing a direct connection between US firms' role in developing the Shtokman gas field and negotiations with the US regarding Russia's WTO entry.

Instead the Kremlin was reflecting its view "in general," said Peskov, adding that the key was "reciprocity."

The US firms which have expressed an interest in joining Russia's Gazprom to develop the 3.7 trillion cubic metre gas field (130 trillion cubic-feet), are ConocoPhillips and Chevron.

Earlier this month, US Vice President Dick Cheney said Russia was trying to use its huge energy resources to intimidate other nations.

Meanwhile Russia says that the demands being made by the US for joining the WTO are harsher than for other countries.

Russia was hoping to join the WTO this summer, but talks with the US over conditions for membership are going slowly.

Further delays

On Wednesday, Gazprom once again postponed choosing a partner firm for the gas field, moving the decision date to "this summer" according to Russia's Energy Minister Viktor Khristenko.

The gas project, which was scheduled to start in 2000, has been repeatedly delayed.

Also keen to partake in the project are French firm Total and Norwegian firms Statoil and Norsk Hydro.

The field is one of the largest in Russia, and could potentially supply both Europe and North America.

Russia will be hosting the G8 summit of world leaders in St Petersburg this summer, with energy security high on the agenda.