11:02

Robert Redfield, the director of the Centers for Disease Control and Prevention (CDC), gave the House oversight committee the latest official figures on the US outbreak - 990 national cases in 38 states plus the District of Columbia, and 31 deaths in the United States.

He said the CDC diagnostic test is now in 75 US public health labs in all 50 states, with the capacity in the public health system to test up to 75,000 people.

On 2 March, the administration promised that a million tests would be available by the end of that week. Carolyn Maloney, the committee chair, wanted to know why the actual number is so much lower and why “South Korea can test more people in one day than we tested over the past two months”.

Redfield said that a test had been developed quickly but added: