(Reuters) - San Antonio Mayor Ron Nirenberg on Monday declared a health emergency for his city in a bid to force those in a federal coronavirus quarantine at a nearby air force base to remain locked down until more testing is done.

Nirenberg said his decision came after a woman was released from quarantine by federal officials on Saturday - only to test positive for coronavirus after she was free. Dozens of evacuees from the Diamond Princess cruise ship in Japan are due to be released from their quarantine at Lackland Air Force base in the coming hours.