BEIJING, April 13 (Xinhua) -- Chinese authorities are strengthening containment measures to identify asymptomatic cases of novel coronavirus disease (COVID-19) at border ports and block the spread of the disease, a customs official said Monday.

Stricter health measures have been taken at air, sea and land ports, Jin Hai, an official with the General Administration of Customs (GAC), told a press conference.

Efforts have been stepped up in the process of detecting asymptomatic cases by promoting health declarations and epidemiological investigations, Jin said.

Starting April 1, all tourists entering the country were required to take a nucleic acid test, and various detecting methods including antibody testing were adopted for more effective detection.

The GAC also established joint prevention and control mechanisms with local authorities, enhancing cooperation and sharing information to ward off infection sources in time, according to Jin.

An earlier meeting of the leading group of China's COVID-19 epidemic response demanded efforts to expand nucleic acid and antibody testing in key regions, calling for raising the testing rate to timely find infected people and obtain the status of asymptomatic coronavirus cases to reduce the risk of virus transmission.