Former President Barack Obama on Saturday criticised American leaders over the handling of the coronavirus response, telling college graduates in an online commencement address that the pandemic shows many officials “aren’t even pretending to be in charge”.

Obama’s criticism comes as eight more American sailors aboard the USS Theodore Roosevelt have tested positive a second time for the new coronavirus.

The development raised to 13 the number who appear to have become infected again while serving aboard the sidelined aircraft carrier, AP news agency reported.

All the sailors had previously tested positive and had gone through at least two weeks of isolation. Before they were allowed to go back to the ship, all had to test negative twice in a row, with the tests separated by at least a day or two.

On Saturday, a Navy official confirmed eight additional sailors had tested positive again. A day earlier the Navy had said in a statement that five had tested positive a second time. The Navy official was not authorised to speak publicly and requested anonymity.

Obama spoke on, Show Me Your Walk, HBCU Edition, a two-hour event for students graduating from historically black colleges and universities broadcast on YouTube, Facebook and Twitter.

“More than anything, this pandemic has fully, finally torn back the curtain on the idea that so many of the folks in charge know what they’re doing,” Obama said without naming the president or other officials. “A lot them aren’t even pretending to be in charge.”