BEIJING, April 13 (Xinhua) -- China has stepped up its fight against illegal border crossings amid mounting efforts to prevent the importation of novel coronavirus disease (COVID-19) cases, an official said Monday.

"Illegal border crossings during the outbreak increase risks of importing COVID-19 cases," said Liu Haitao, a division head of the National Immigration Administration, at a press conference Monday.

Residents at border regions are urged to report signs of illegal border crossing to authorities in a timely manner, Liu said.

Among illegal border-crossing cases, he spoke of the investigation of three major cases of organized illegal border crossings by border authorities in southern China's Yunnan and Guangxi, which led to the interception of a number of people attempting to cross the border illegally.

Drivers transporting travelers that illegally cross the border and hotel managers failing to register their information have also been held to account by the law, said Liu.