​US aircraft have recently returned to targeting al Qaeda and Khorasan Group targets in Syria, temporarily taking attention away from ISIS but still targeting groups that are enemies of the US and allies, a spokesman for the US-led coalition said. US aircraft on Sunday killed a senior al Qaeda leader who was affiliated with the Khorasan group in Syria. “These groups don’t necessarily work together,” said Army Col. Steve Warren, spokesman for Combined Joint Task Force-Operation Inherent Resolve, during a Thursday briefing. “But, they are part of the same disease” that works to export terror. The strike against the Khorasan group was the first in less than 18 months, Warren said. The mission against al Qaeda has been ongoing since Sept. 11, 2001, and has been through “ebbs and flows” in Iraq and Syria. “These al Qaeda and Khorasan Group operatives, we know have one main goal, and that is to plan attacks in the west,” Warren said. “That is what they did. So we are out looking for them. As the pressure continues to ​mount, they become exposed ... whether it's through their own mistakes or whether it's just through good work that we do.” Still, the coalition has continued its offensive against ISIS, with the most recent tally of strikes from April 5 including 19 attacks against ISIS targets in Iraq and four in Syria.