The 143-year-old LME is set to suspend its open out-cry ring trading, and NYSE owner Intercontinental Exchange said the NYSE equities trading floor, American Options trading floor and the NYSE Arca Options trading floor in San Francisco would be temporarily closed.

"While we are taking the precautionary step of closing the trading floors, we continue to firmly believe the markets should remain open and accessible to investors," NYSE president Stacey Cunningham said.

"NYSE's trading floors provide unique value to issuers and investors, but our markets are fully capable of operating in an all-electronic fashion to serve all participants, and we will proceed in that manner until we can re-open our trading floors to our members."

The LME had been planning to move ring trading to its back-up site in Chelmsford starting from March 18 to minimise the transit of personnel through London, but due to new precautionary measures said it would continue at 10 Finsbury Square to March 20.

"Ring trading would then be suspended until conditions normalise in respect of COVID-19, at which point ring trading will resume," the LME said.

"During this period, trading will be conducted via LMEselect and the inter-office market."

It said it had fielded "a number of questions and concerns" about the possibility of market tightness or physical disruption and said it expected its listed warehouses to have robust procedures in place to deal with the effects of COVID-19.

However it acknowledged it was "foreseeable" that a delivery point or warehouse could be forced to shut.

"Given these risks, the LME has developed procedures to manage the temporary unavailability of a warehouse or delivery point as a result of Covid-19, in line with the provisions of the Warehouse Agreement and addressing potential issues around both delivery obligations, warranting, and rent payments," it said.