India, the No. 2 importer of crude from Russia, wants to buy Russian oil only if it is supplied by companies and ships that have not been sanctioned by the United States, the country's oil secretary said.

A huge and growing amount of Russian and Iranian oil is stuck on tankers worldwide as Western sanctions continue to impede cargo delivery, experts believe, Oil prices and freight rates are up amid a lack of suitable vessels, while fewer Chinese and Indian refiners are willing to receive barrels on blacklisted ships.

Russia's oil production may decrease due to U.S. sanctions affecting tanker access and Ukrainian drone attacks crippling refineries. With limited storage and falling exports, output cuts are likely. Russia's economic strain grows as global buyers demand non-sanctioned tankers and lower crude supply impacts revenue.

The amount of Russian and Iranian oil held on ships has hit multi-month highs as harsher U.S. sanctions reduced the number of buyers, leaving fewer tankers available to deliver cargoes and driving up crude costs,

U.S. sanctions on Russia should not affect Moscow's oil trade with India, Pavel Sorokin, Russia's first deputy energy minister, said on Tuesday, while adding it was too early to assess the impact of the latest restrictions.