The Shanghai Cooperation Organisation summit is being held in the northern port city of Tianjin until Monday, days before a massive military parade in the capital Beijing to mark 80 years since the end of World War II.

The SCO comprises China, India, Russia, Pakistan, Iran, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan and Belarus -- with 16 more countries affiliated as observers or "dialogue partners".

Russian President Vladimir Putin touched down in Tianjin on Sunday with an entourage of senior politicians and business representatives.

Xi held a flurry of back-to-back bilateral meetings with leaders including Belarusian President Alexander Lukashenko -- one of Putin's staunch allies -- and India's Prime Minister Narendra Modi, on his first visit to China since 2018.

Modi told Xi that India was committed to taking "forward our ties on the basis of mutual trust, dignity and sensitivity".

Xi, in turn, told Modi that he hoped the two countries would recognise that they are "partners rather than rivals".

If they see each other as "opportunities for development rather than threats", China-India relations will grow steadily, Xi added, according to state broadcaster CCTV.

The two most populous nations are intense rivals competing for influence across South Asia and fought a deadly border clash in 2020.

A thaw began last October, when Modi met with Xi for the first time in five years at a summit in Russia.

"The interests of 2.8 billion people of both countries are linked to our cooperation. This will also pave the way for the welfare of the entire humanity," Modi told Xi.

- 'Project influence' -

The bilateral talks were held at the Tianjin Guest House, an intimate venue surrounded by lush greenery.

Security guards positioned themselves around and inside the venue, their eyes scanning reporters and guests carefully, as Chinese diplomats hurried through the halls.

Large sections of Tianjin were closed to traffic, with a significant police presence deployed around the city.

Official posters promoting the SCO lined the streets, displaying words such as "mutual benefit" and "equality" written in Chinese and Russian.

China and Russia have sometimes touted the SCO as an alternative to the NATO military alliance. This year's summit is the first since US President Donald Trump returned to the White House.

As China's claim over Taiwan and Russia's invasion of Ukraine have seen them clash with the United States and Europe, experts say that Beijing and Moscow are eager to use platforms such as the SCO to curry favour.

"China has long sought to present the SCO as a non-Western-led power bloc that promotes a new type of international relations, which, it claims, is more democratic," said Dylan Loh, an assistant professor at Singapore's Nanyang Technological University.

More than 20 leaders including Iranian President Masoud Pezeshkian and his Turkish counterpart Recep Tayyip Erdogan are attending the bloc's largest meeting since its founding in 2001.

- Talks on the sidelines -

Putin is expected to hold talks on Monday with Erdogan and Pezeshkian about the Ukraine conflict and Tehran's nuclear programme respectively.

Xi met Erdogan on Sunday to discuss the situations in Gaza and Ukraine, a readout from Ankara said.

Turkey has hosted three rounds of peace talks between Moscow and Kyiv this year that have failed to break the deadlock over how to end the conflict.

The Russian president needs "all the benefits of SCO as a player on the world stage and also the support of the second largest economy in the world", said Lim Tai Wei, a professor and East Asia expert at Japan's Soka University.

"Russia is also keen to win over India, and India's trade frictions with the United States presents this opportunity," Lim told AFP.

The summit comes days after India was hit by a sharp bump up in US tariffs on its goods as punishment for New Delhi's purchases of Russian oil.

Many of the assembled dignitaries will be in Beijing on Wednesday to witness the military parade, which will also be attended by North Korean leader Kim Jong Un.