Russia and China are at an "active stage" of talks on a proposed new gas pipeline, the Power of Siberia-2, carrying Russian gas via Mongolia to China, but are unlikely to sign a contract in the next couple of days, Energy Minister Sergei Tsivilev said, according to Russia state news agency TASS.
Chinese President Xi Jinping is in Moscow this week for celebrations to mark the 80th anniversary of victory over Nazi Germany in World War Two.
"The companies are working on the contract. They are in the active stage of negotiations, so I think it is unlikely - there are one or two days left - that they will manage to do this before May 9," he said, referring to Thursday's war anniversary.
Russia has been seeking an agreement with Beijing for years on building the Power of Siberia-2 to carry 50 billion cubic metres of natural gas a year from the Yamal region in northern Russia to China via Mongolia.
So far, however, the parties have not been able to agree on the terms of gas deliveries.
China's ambassador to Russia said last month that the route for the pipeline had yet to be defined.
Russia proposed the route years ago but the plan has gained urgency as Moscow looks to Beijing to replace Europe as its major gas customer.
Xi in Moscow
Putin and Xi approached each other along a red carpet from opposite ends of one of the Kremlin's most opulent halls and shook hands in front of the cameras, then stood to attention for the playing of the Chinese and Russian national anthems.
"Together with our Chinese friends we firmly stand on guard of historical truth, protect the memory of events of the war years and counter modern manifestations of neo-Nazism and militarism," Putin said.
Xi is the most powerful of more than two dozen foreign leaders who are visiting Moscow this week to mark Thursday's 80th anniversary of the end of World War Two.
The celebrations are taking place at a key moment in the war with Ukraine, as Moscow and Kiev come under US pressure to reach a peace deal.
Key element of Russia's energy strategy faces a hurdle as China wants to pay less and buy less gas than Moscow proposed for the Power of Siberia 2 pipeline.
Ceasefire
Ukraine's air force reported air strikes on its northern region of Sumy on Thursday morning as Putin's order for a three-day truce with Ukraine was supposed to take effect.
"As of 08:00 am, no missile attacks or attack drones were recorded in Ukrainian airspace. However, during the night, the enemy intensified tactical aviation strikes using guided aerial bombs in the Sumy region," the air force said, after reporting several launches in the morning.
Kiev has declared an air alert in its seven eastern regions, stating that there is a danger of Russia using ballistic missiles, the Ukrainian air force said on Thursday.
