BEIJING, July 1 (Reuters) - China will loosen entry restrictions on U.S. citizens, allowing entrance in case of transit via a third country, notices issued late on Friday by the Chinese embassy in Washington said, relaxing rules imposed in Beijing's drive to curb COVID-19.

China's "dynamic COVID zero" policy, which aims to minimise the risk of infected travellers arriving from abroad, has resulted in many barriers to international travel, from restrictions on the issue and renewal of passports for Chinese citizens to tough quarantine requirements upon arrival.

According to an updated policy statement, U.S. citizens with valid negative COVID test results looking to enter China may now apply for and receive a green health code for travel in from either the United States or a third country. In the past, the embassy would only grant the codes to U.S. citizens flying directly from the United States.

China has loosened the same restrictions recently for citizens of other countries.

The restrictions, coupled with a limited number of direct flights from the United States to China, caused ticket prices to cost as much as $10,000.

The changes follow a similar slight relaxation of COVID testing rules for people arriving in China from countries including the United States announced on May 18.