The killing of Iranian military commander Qassem Soleimani sparked new concerns among American intelligence officials about danger to U.S. troops in Iraq. Officials have told members of Congress in multiple briefings that they worry Shiite militias in Iraq may be more likely to target U.S. forces without Soleimani’s strategic influence, according to four people familiar with the intelligence briefings. One of the sources said concerns include the possibility that the militias may try to avenge Soleimani’s death by targeting U.S. troops.

Another said Soleimani acted as “somewhat of a check” on the militias, and that no other Iranian official has the same ability to keep them from operating without a strategy. The New York Times reported that U.S. intelligence agencies recorded “vague” threats made against Iraq’s Al-Assad air base hours before Iran fired missiles on Tuesday, with one warning of the possibility that “hundreds of fighters from Kataib Hezbollah, an Iraqi militia trained and equipped by Iran, might launch a frontal assault on the base.”