Maj.Beth Riordan, a spokeswoman for Pentagon Central Command, said seven senior al-Qaida leaders were killed in a meeting near Idlib on Thursday.

“AQ-S is taking advantage of the instability in northwest Syria to establish and maintain safe havens to coordinate terrorist activities,” Major Riordan said in a post-strike email using a military abbreviation for Hurras al-Din. “The removal of these AQ-S leaders will disrupt the terrorist organization’s ability to continue planning and conducting global attacks that threaten US citizens, our partners and innocent civilians.”

Just a week earlier, on October 15, several al-Qaida activists were killed in a similar hellfire missile drone attack also near Idlib, Major Riordan said, without disclosing further details.

Charles Lister, director of the Middle East Institute’s Syria and Counter-Terrorism and Extremism Program, said one of those killed in the October 15 strike was Abu Mohammed al-Sudani, an al-Qaeda veteran who worked with both Osama Bin and them I’m close to Laden and Mr. al-Zawahri.

The United States has no troops on the ground in northwest Syria, but the military’s secret Joint Special Operations Command, with the help of the CIA, is waging a shadow war against Hurras al-Din, a small but virulent al-Qaeda subsidiary of American officials say is planning attacks against the west.

The two most recent strikes have been carried out using conventional hellfire missiles equipped with an explosive warhead of around 20 pounds, military officials said. Special forces are also using a new variant of Hellfire, the R9X or Ninja, to hunt down individual al-Qaeda leaders in locations where the military is trying to avoid civilian casualties.

Instead of exploding, the modified hellfire hurls about 100 pounds of metal through the top of a target’s vehicle. If the high-speed projectile doesn’t kill the target, it’s almost certainly the missile’s other characteristic: six long blades hidden inside that unfold seconds before impact to cut something on its path.