President Donald Trump has criticised the trade relationship between the US and India, calling it a "totally one-sided disaster."

"What few people understand is that we do very little business with India, but they do a tremendous amount of business with us," Trump wrote on his social media platform Truth Social on Monday.

"In other words, they sell us massive amounts of goods, their biggest 'client,' but we sell them very little - Until now a totally one-sided relationship, and it has been for many decades," he added.

Trump’s 50 percent tariffs on imports from India took effect late last month, partly as a punishment for importing Russian oil. Earlier, the US president imposed a 25 percent baseline tariff on Indian goods.

Accusing India of maintaining high import tariffs that limited US access to its market, Trump said: "The reason is that India has charged us, until now, such high Tariffs, the most of any country, that our businesses are unable to sell into India."

Also noting India's energy and defence purchases from Russia, he said, "India buys most of its oil and military products from Russia, very little from the US. They have now offered to cut their Tariffs to nothing, but it's getting late."

"They should have done so years ago," he added. "Just some simple facts for people to ponder!!!"

Trump's post came shortly after a Shanghai Cooperation Organisation (SCO) summit concluded in China's Tianjin, where leaders adopted a 10-year development roadmap and agreed to boost economic and security ties.

Bringing together about 20 heads of state and government, along with leaders of international organisations, the SCO summit was one of the largest gatherings of the organisation, marking the fifth time China has hosted it since the bloc was formed in 2001.

As US tariffs roil international markets, the SCO leaders expressed support for a multilateral trading system.