China on Thursday announced the opening of a new rail and road trading route to Nepal, coming amid fresh strains in the country's relations with India following the cancellation of its president's visit and the recalling of its envoy from New Delhi earlier this week.

Months of strains in ties with India, first sparked by unrest over the new Constitution and an ensuing trade blockade, has seen Kathmandu turning increasingly to Beijing, primarily to step up fuel imports amid an energy crisis caused by the blockade.

Further tensions were triggered this week after Nepal announced the cancellation of a scheduled visit by its president to India, with Kathmandu blaming New Delhi for what it described as efforts to destabilise Prime Minister KP Sharma Oli's government.

In March, China told Oli when he visited Beijing that it would back his government against "any external interference", and would support stability in Nepal and aid his government within its capacity, with trade and investment. Oli had during the visit secured a landmark deal with China for extending its Tibet railway network into Nepal, a long-discussed proposal that Nepal had in the past spurned because of Indian sensitivities. In a reversal, Chinese officials said it was Oli that raised it in Beijing.

As both sides shortly begin a feasibility study into the railway plan, Beijing on Thursday flagged off a new rail-cum-road trading route, with an international freight train loaded with 86 cargo containers carrying goods from China's western Gansu province bound for Kathmandu.

The train will halt at Xigaze in Tibet, the last point on the Tibet railway network in the west, with the goods then transferred to road transport until Kathmandu.

The journey will take 10 days, according to Chinese State media reports, covering three sections: 2,431 km from Gansu's provincial capital Lanzhou by rail to Xigaze; 564 km over land to the border port of Gyirong, and a 160 km from the Nepal border to Kathmandu.

The new route, reports said, would take "35 days fewer than traditional ocean transport would".

Chinese Foreign Ministry official Hou Yanqi, Deputy Director General in the Asia Department, told India Today in March during Oli's visit that China was already extending the Tibet railway network from Xigaze to Gyirong.

Oli, she said, had proposed extending the line from Gyirong into Nepal. "Prime Minister Oli raised proposals of two kinds of railways," said Hou. "The first is projects [within the territory] of Nepal connecting the three biggest cities in Nepal, and the second is a cross border railway," she said. The proposal, she added, had "got a positive response from the Chinese side and the two sides have agreed to conduct feasibility study at an early date."