Biden’s senior adviser on global energy security, Amos Hochstein, said on Monday that Russian President Vladimir Putin was close to using natural gas as a political tool.

“I think we are close to this limit if Russia actually has gas for supplies and does not do so, and will only do so if Europe agrees to its other requirements, which are completely unrelated,” Hochstein told reporters in response to the question of whether President Putin uses gas as a weapon.

Hochstein said gas prices in Europe had risen not only because of developments in the region, but also because of the dry season in China, which has reduced hydropower production and intensified global competition for natural gas.

According to him, despite the fact that the European gas crisis was caused by several factors, Russia is in the best position to help Europe.

“I have no doubt, and (the International Energy Agency) has confirmed that the only supplier that can really be important for European energy security at the time of this winter is Russia,” Hochstein said.

According to him, Russia can increase gas production and do so quickly with the help of existing pipelines.

Putin has previously rejected assumption that Moscow is cutting supplies for political reasons, saying it will increase supplies as much as partners ask.

Putin blamed EU energy policy for record high prices and said Russia could increase supplies to Europe once its Nord Stream-2 gas pipeline was approved.

The head of Ukraine’s state-owned energy company, Naftogaz, Yuri Vitrenko said this month that Russia was trying to blackmail Europe to certify its Nord Stream-2 gas pipeline by limiting fuel reserves.

According to Hochstein, the approval of Germany and the European Commission for Nord Stream-2 is likely to last until March. Therefore, if Russia says it can quickly increase gas flow through Nord Stream 2, it should be able to do so now through existing pipelines.