Russia's President Vladimir Putin, right, and China's President Xi Jinping review an honor guard during a welcome ceremony at the Xijiao State Guesthouse Tuesday. Pic: AP.

SHANGHAI (AP) — A spokesman for Russia’s Gazprom says the company has signed a long-awaited, 30-year contract to supply natural gas to China.

Spokesman Sergey Kupriyanov told The Associated Press the deal was signed Wednesday but he declined to give any price details.

The sale is a financial and diplomatic boost for Moscow, which is isolated in the West over the Ukraine crisis. The supplies should help China ease gas shortages.

China and Russia have been negotiating the deal for more than a decade but had been hung up over the gas price.

Chinese and Russian officials had said they expected a deal to be reached in time to be signed during this week’s visit to Shanghai by Russian President Vladimir Putin.