The Chinese government sharply criticized COVID-19 testing requirements imposed on visitors from China and threatened countermeasures against countries involved, which include the U.S. and several European nations.

“We believe that the entry restrictions adopted by some countries targeting China lack scientific basis, and some excessive practices are even more unacceptable,” Foreign Ministry spokesperson Mao Ning said at a daily briefing Tuesday.

“We are firmly opposed to attempts to manipulate the COVID measures for political purposes and will take countermeasures based on the principle of reciprocity,” she said. Mao did not specify what steps China might take.