The Seoul city government reiterated Monday the U.S.-based taxi-calling service Uber is illegal under local law, pledging to crack down on its activities.

Opposition among local taxi drivers has grown since the launch of the app that links passengers with registered drivers in August, 2013. 

The city council of Seoul passed an ordinance on Friday that would offer a financial reward of up to 1 million won (US$910.5) for those who report Uber's illegal activities, among other things.

Uber has, however, vowed to continue its business despite the new ordinance.

"Uber impairs the value of a shared economy based on sharing and participation carried out inside the legal framework," said Kim Kyung-ho, the head of the city traffic division of the city government. "(The city) will strictly crack down on drivers and rental cars that cooperate with Uber and adopt a financial rewards system to restore order in the transportation sector," he said.

The city has repeatedly filed complaints with the prosecution against Uber Korea and some rental car firms while proposing a law revision to drive out the smartphone-based service, the city said. 

The city asserted the illegality of the service that recruits drivers who are not locally registered as taxi drivers and does not comply with fare regulations. 

Uber, when operating outside the law, cannot guarantee the safety of passengers, the city said. 

Uber, first launched in 2010 in San Francisco, has met with similar opposition from taxi drivers in other countries. (Yonhap)