The Chinese headline sponsor of the Indian Premier League, the world's richest cricket tournament, is set to withdraw amid mounting hostility after a border clash between the Indian and Chinese armies, reports said.

Phonemaker Vivo was to pull out from backing at least this year's tournament, which has been switched to the United Arab Emirates because of the coronavirus pandemic, the reports said. There have been widespread calls for a boycott of Chinese goods in India since the June 15 clash in the Himalayas in which 20 Indian troops were killed.

Vivo paid $330 million for a five-year deal up to 2022 but has faced opposition since the deadly clash which also left an unknown number of Chinese casualties. The Indian government has already banned dozens of Chinese smartphone apps, including the video sharing platform TikTok, and taken other measures that will restrict trade with China.

There was no immediate comment from Vivo or the Board of Control for Cricket in India but the reports said they were negotiating a way for the Chinese firm to exit the deal. Press Trust of India news agency quoted a BCCI official as saying that both sides wanted "an amicable escape route".

The BCCI had said after the clash that it would "review" its IPL sponsor deals. A backlash erupted on Sunday when it announced that Vivo would remain the main sponsor for the much-delayed tournament which will now start on September 19.

The Confederation of All India Traders, which claims 70 million small business members, said the Indian government should block the IPL tournament for showing "utter disregard" to public anger over the border deaths.

Swadeshi Jagran Manch (SJM), the cultural arm of the influential Hindu nationalist Rashtriya Swayamsevak Sangh (RSS), which is close to the government of Prime Minister Narendra Modi, threatened a boycott of the IPL unless the Chinese sponsor was dropped.

"We want to urge the IPL organisers to reconsider their stand on sponsorship by Chinese companies," said an SJM statement. "Please remember the nation's pride and security above all," it added. There was also widespread social media outrage.

Chinese officials have expressed concern and warned of reprisals over the measures already taken in India that is starting to freeze their enterprises out of the giant market of 1.3 billion people. The BCCI was in talks with Indian companies about stepping in for this year but expected to make less than the $60 million it would have got from Vivo, PTI said.