SHANGHAIBEIJING, May 25 Reuters Great Wall Motor has filed a report with China39;s regulators against BYD, it said on Thursday, claiming its rival39;s two topselling hybrid models did not meet emissions standards and triggering a rare public spat.

BYD rejected the claim, saying its vehicles met China39;s emission standards and that it reserved the right to take legal action against Great Wall.

The public accusation from Hebeibased Great Wall China39;s first listed car maker has thrown it into an unusual, open fight with BYD, the country39;s largest and most successful maker of electric and plugin hybrid vehicles that has emerged as a rival to Tesla.

Hong Konglisted shares of Great Wall closed down 7.3. Hong Konglisted shares of BYD fell 5.4.

On its WeChat account, Great Wall Motor said it had submitted documents on April 11 to China39;s ecology and environment ministry, the industry and information ministry and the top market regulator alleging that BYD failed to meet pollutant emissions standards in two plugin hybrid models.

The three government agencies did not immediately respond to a request for comment from Reuters.

We firmly oppose any kind of unfair competitive behaviour and reserve the right to sue, BYD said in a statement.

Great Wall Motor accused BYD of using nonpressurised fuel tanks in its Qin Plus and Song Plus plugin hybrids, which let the liquid inside evaporate more rapidly than it would in pressurised tanks.

The Song is BYD39;s bestselling…