The coronavirus outbreak in Iran could lead to an increase in Tehran-sponsored attacks on the U.S. and its allies, the top U.S. military commander in the Middle East said Thursday.

Regimes like Iran’s tend to look to external threats during moments of crisis, Marine Gen. Kenneth “Frank” McKenzie of U.S. Central Command told the Senate Armed Services Committee. While McKenzie cautioned that he and his staff have limited visibility into Iran and the effect of the Coronavirus outbreak there, “it probably makes them, in terms of decision-making, more dangerous rather than less dangerous,” he testified.

The outbreak already appears acute in Iran, despite regime attempts to tamp down word of its impact. Its health minister tested positive for the virus shortly after asserting it was under control. On Thursday, the Washington Post reported that satellite photography indicates the construction of mass graves for Coronavirus casualties near Qom.

McKenzie’s testimony came the morning after the Pentagon confirmed that two U.S. servicemembers and a U.K. colleague were killed in a rocket attack on Camp Taji in Iraq, a violation of President Trump’s “red line,” and at least 12 others were wounded. The attacks raised fears that, as predicted, Iranian-sponsored reprisals for the January killing of external-security chief Gen. Qassem Soleimani in a U.S. drone strike were ramping up after an interval of relative quiet.

McKenzie did not affirmatively attribute blame for the lethal rocketing of Taji, but indicated he considered the Iranian proxy militia Kata’ib Hezbollah a prime suspect.

After a wave of varying explanations for the assassination of Soleimani, Secretary of State Mike Pompeo and other officials explained the slaying as “re-establishing deterrence” against Iran. But several senators of both parties, including armed-services chairman Sen. Jim Inhofe (R-Okla.), pointed out that the Taji attack suggested that no such bolstered deterrent has manifested. Nor has the dramatic escalation of U.S. forces to the Middle East since May – a figure McKenzie placed at an additional 10,000 U.S. troops, rather than the oft-cited 14,000 figure.

“While periods of decreased tension may provide the illusion of a return to normalcy, ample intelligence exists indicating the Iranian regime’s desire to continue malign operations that threaten lives, disrupt the internal matters of sovereign nations, and threaten freedom of navigation, regional commerce, global energy supplies, and the global economy,” McKenzie testified.

Pressed by senators, McKenzie said that the Soleimani assassination – a word he did not use – had restored “a rough form of deterrence,” by which he meant direct state conflict. But proxy attacks, which are by far the more typical mode of Iranian operation against U.S. forces over the past 15 years, have not ended, even with the Soleimani killing and the force buildup.

That U.S. force escalation ought to continue, McKenzie judged, “so long as we continue a Maximum Pressure campaign” against Iran. He conceded that the U.S. might have to “ultimately live with a low level of proxy attacks.”

McKenzie offered no connection between the Coronavirus outbreak and Wednesday’s rocketing of Camp Taji. But he revealed a different Coronavirus episode: a CENTCOM contractor has displayed symptoms of the virus. That person, as yet unnamed, has been placed in quarantine, as has another person who interacted with that person, McKenzie stated.