China's National Administration of Surveying, Mapping and Geoinformation has published a list of 19 domestic websites that have offered online mapping services without obtaining permission, warning them to apply for approval before Friday.

Similar websites that fail to obtain or apply for permission before the deadline will face punishment, said a statement issued by the administration Wednesday.

Illegal online mapping services sometimes leaked confidential geographic information and made mistakes in drawing the country's borders, the statement said.

It said that the administration issued warnings to 46 illegal online mapping service websites last month, and had received permission applications from many of the websites thereafter.

As of Wednesday, a total of 197 websites across the country were qualified to provide such services, the statement said.

China introduced a new licensing system for Internet mapping services last May and required all providers to get a license before the end of March.