David Petraeus, the commander of US forces who led the anti-insurgency push in Iraq, has called for millions of Americans to be tested for Covid-19 as the country moves to war footing against the pandemic. Mr Petraeus said mass testing was the most effective response to the crisis sweeping the US. "That's what we should be doing for any area where we suspect there are people who have contracted coronavirus," he said. The former CIA director and general called for the establishment of a "national service" of Americans administering tests to their fellow citizens, and helping to oversee the quarantine of those testing positive. Contact-tracing people and those sent to support those facing the challenges in isolation could be recruited by appealing to their sense of patriotism and generosity. "It is appropriate to talk about some kind of national service that could be employed," Mr Petraeus said. He told an online seminar at the London School of Economics that talk of wartime conditions and mobilisation was a fair comparison for the challenge posed by the pandemic. "I don't think it is unreasonable to liken this to a war," Mr Petraeus said. "In the US we have lost more in one month, in April, than we lost in the Vietnam war." He spoke of his admiration for Jacinda Ardern, the Prime Minister of New Zealand, who has declared the country is "halfway down Everest" as new infections have been wiped out. "She has been hugely impressive, getting the big ideas across, and relentless," he said. America has the highest infection number with 1.33 million people contracting Covid-19. The death toll was 79,606 on Monday. New Zealand, a much smaller nation, shut its borders on March 15 and kept the number infected below 1,500.