HANOI, Aug 20 (Reuters) - Vietnam will deploy troops in Ho Chi Minh City and prohibit residents from leaving their homes, authorities said on Friday, as the country"s biggest city turns to drastic measures to slow a spiralling rate of coronavirus deaths. Vietnam"s toughest order yet comes amid a spike in fatalities and infections, despite weeks of lockdown measures in the business hub of 9 million people, the epicentre of the country"s deadliest outbreak. "We are asking people to stay where you are, not to go outside. Each home, company, factory should be an anti-virus fort," Pham Duc Hai, deputy head of the city"s coronavirus authority, said on Friday. The government said it was preparing to mobilise police and military to enforce the lockdown and deliver food supplies to citizens. Police with loudspeakers were seen driving around residential areas on Friday instructing people to follow protocols and assuring them food supplies would be provided. The defence ministry plans to send 1,000 military medics and medical equipment over the weekend, according to a military document reviewed by Reuters. The government also extended restrictions on Friday in the capital Hanoi by a further 15 days, state media reported. News of the worsening coronavirus crisis hit Vietnam shares on Friday, with its benchmark index (.VNI) closing down 3.3%. Vietnam has been slow to procure vaccines and until late April had one of the world"s best containment records, with 35 deaths and just over 2,900 cases as of May 1. But that has since jumped to over 312,000 cases and 7,150 deaths, with about half of the infections and 80% of fatalities in Ho Chi Minh City alone. Half of Ho Chi Minh City residents have received at least one dose of a COVID-19 vaccine, but at a meeting late Thursday, Prime Minister Pham Minh Chinh ordered authorities to conduct mass testing there too. "If you fail to test them all within the next two weeks, it would be your fault," Chinh told health minister Nguyen Thanh Long at the meeting, according to state broadcaster VTV. Editing by Martin Petty Our Standards: The Thomson Reuters Trust Principles.