Russia's Petrovax has started a late-stage trial of a COVID-19 candidate vaccine from CanSino Biologics Inc. in the country, records show, as the Chinese drug firm steps up testing abroad to close in on regulatory approval.

The Ad5-nCoV vaccine already has approval for use by China's military after early and mid-stage trials and further late-stage trials are being lined up for Mexico and Saudi Arabia.

CanSino last month said it was in talks for opportunities to launch late-stage – or Phase 3 – trials in Saudi Arabia, Russia, Brazil and Chile.

The vaccine was granted the first invention patent by Chinese authorities on Sunday, which the company said further confirmed the vaccine's efficacy and safety and convincingly demonstrated the ownership of its intellectual property rights.

This is the first trial of a potential vaccine developed by a foreign company to take place in Russia, while the country prepares to start mass production of its domestic shot developed by Moscow's Gamaleya Institute.

Russian pharmaceutical company Petrovax confirmed in a statement on Saturday it was running the trial for CanSino.

If the vaccine is approved in the country, it said it would also produce the shot at its facilities in the Moscow region, with plans to supply the Russian market, as well as CIS countries.

Russia's state register for clinical trials showed a phase 3 study of CanSino's potential shot, expected to recruit 625 participants across eight medical institutes to test the safety and effectiveness of Ad5-nCoV, began on Friday.

China's top respiratory expert Zhong Nanshan said at a symposium on Saturday that China and Russia have plans to jointly carry out clinical trials of vaccines.

The symposium, joined by medical experts from the two countries, focused on deepening the bilateral cooperation on COVID-19 containment, aiming to boost new progress in their fight against COVID-19.

Zhong said he pays close attention to the epidemic situation in both China and Russia, and the two countries "have much to learn from each other."

Russia's case fatality rate, at around 1.7 percent, is low, and the techniques and strategies are worth learning, while China has its own unique methods of fighting the epidemic, especially in applying traditional Chinese medicine, Zhong said.

(With input from Reuters)