COLOMBO (AFP) - Sri Lanka's capital will go back into lockdown from Friday (Oct 30) following a surge in coronavirus cases, the authorities said on Thursday.

The South Asian island nation of 21 million people has reported more than 9,200 Covid-19 infections, with over half detected in the past three weeks after more than a thousand garment factory workers tested positive. There were 19 deaths recorded in the country.

Around 5.5 million people living in the capital Colombo and two neighbouring districts would be allowed to move around only for essential services, health officials said.

The lockdown for three days could be extended depending on the pace of infections, they added.

"The curfew comes into effect from midnight, but we are trying to discourage any non-essential travel across provincial borders from today," police spokesman Ajith Rohana told AFP.

Soldiers carried out random temperature checks on pedestrians and motorists in Colombo on Thursday.

Sri Lanka imposed a three-month lockdown until the end of June, with the authorities lifting the restrictions after declaring that there was no community transmission of the virus.

The new measures followed a 12-hour visit to Colombo by US Secretary of State Mike Pompeo, who laid a wreath and prayed at St Anthony's Roman Catholic church, the site of a deadly attack during last year's Easter Sunday suicide bombings.