BEIJING -?China is to crack down on sales or uploads of classified maps on the Internet to curb geographic information leaks, authorities announced on Friday.

The campaign will focus on online trade in classified basic surveying and mapping results, and digital navigation maps without confidential treatment, the National Administration of Surveying, Mapping and Geoinformation said in a statement.

It plans to inspect e-commerce websites, blogs and bulletin boards.

People found illegally selling or providing classified maps will be harshly punished, while websites containing sensitive geographic information will be shut down, according to the statement.

The administration will also check maps providing tourist or traffic information to make sure they are not carrying excessive commercial advertisements, it said.