Shanghai authorities have fined ride-hailing service providers Didi Chuxing and Meituan Dianping for using unlicensed vehicles and warned their smartphone apps could be suspended if they continue to fail to meet standards.

The fines are the latest in a crackdown on illegal practices in China's fast-growing ride-hailing industry.

Shanghai's transportation and communications authorities have fined Didi 200,000 yuan ($28,400) for providing services with unlicensed vehicles, the Shanghai transportation commission said on its WeChat social media account on Tuesday.

The commission noted that Didi had already been fined 5.5 million yuan during the last assessment of the industry in July.

It said the authorities had also fined Meituan Dianping 30,000 yuan, following a 1.47 million yuan penalty last month.

Local government data showed that about 80 percent of the unlicensed vehicles spotted by the latest assessment were hired by Didi and more than 15 percent were hired by Meituan Dianping.

It warned that regulators could suspend ride-hailing services' smartphone apps if they failed to meet requirements published by the government in 2018.

Didi said it is actively communicating with authorities and will continue to promote the compliance of ride-hailing vehicles. Meituan Dianping declined to comment.

China toughened rules on ride-hailing services last year after a number of high-profile incidents, including the killing of two passengers, that stoked public anger. 

It ordered companies to suspend drivers without proper operating licenses and stop new registrations for unqualified drivers. Since then, Didi has been working on improving safety measures.