BEIJING, June 3 -- Beijing transport authorities have reiterated the illegality of unlicensed taxis after grilling executives of Uber-like taxi-hailing app Didi Dache at a meeting on Tuesday.

Didi Dache services "Didi Express" and "Didi Zhuanche", which allow private car owners to accept fares for driving passengers around, violate existing laws and regulations, according to a statement released by the Beijing Municipal Transportation Commission and Traffic Law Enforcement Agency.

Only cars officially designated as taxis may pick up paying passengers, said the statement.

"Didi Express" charges slightly less than taxis. "Didi Zhuanche" charges at least 30 percent more than taxis but is still appealing thanks to frequent coupons.

Didi, which is backed by Chinese Internet giant Tencent and has more than 100 million registered users, also runs another two services that were not mentioned in the statement. One allows users to hail standard taxis. Another, launched only on Monday, is designed for ride-sharing.

The market for taxi-hailing apps has boomed in China since Didi launched in 2013, serving massive demand for public transport.

Beijing has 66,000 taxis, about the same number as it did 20 years ago. In that time, Beijing's population has doubled and the same can be said for many other Chinese cities. Of those 66,000, most are operated on licenses granted before 1994.

While the apps have been welcomed by the public, they have been subject to sporadic government crackdowns, and taxi drivers have organized strikes protesting the lack of regulation of Didi and Uber.

Beijing traffic police have dealt with 963 cases of unlicensed taxis this year. More than 200 cases involved Didi cars.

Following Tuesday's meeting, a Didi executive promised to "correct the company's behavior according to government requirements and strengthen its cooperation with relevant government institutions".

Didi will make its data concerning drivers, vehicles and transactions available to the government, the executive said.