Homegrown violent extremists are a particular worry. In an interview, John Demers, the assistant attorney general for national security at the Justice Department, said the department and the FBI are closely monitoring how the virus is shaping their plans.

“They do get ideas about, ‘How can I try to weaponize this virus?’” he said. “It’s something we’re focused on, together with the FBI — and making sure on the intel side that we’re on top of whatever’s showing up.”

Officials are also tracking the way the pandemic could influence terrorists’ strategies on timing and targets for more conventional attacks, Demers said.

“Are they going to accelerate any of their plans?” he said. “Are they going to see windows of opportunities? Obviously a lot of public places are less crowded, but others, like hospitals, are more crowded. Are they going to see these windows of opportunity to take advantage of?”