And is anyone buying the “we’ve killed 15K” claim?

WASHINGTON — In a sign of its resilience, the Islamic State appears to have recruited new fighters to offset 15,000 militants killed in a U.S.-led airstrike campaign approaching its first anniversary, U.S. military and intelligence estimates show.

More than 5,500 airstrikes by a U.S.-led coalition in Iraq and Syria that began Aug. 8, 2014, have forced the extremist organization to disperse its fighters into smaller groups, making them less of a threat to seize large chunks of territory, according to the military estimates. Despite the lethal strikes, the group continues to attract new recruits and replace leaders, highlighting the difficulty of fighting a movement that draws support from Muslims around the world.

A year ago, the CIA said it believed the Islamic State had between 20,000 and 31,500 fighters in Iraq and Syria. The estimate remains the same this year, according to a U.S. intelligence official, who asked not to be named since he was not authorized to discuss the issue.

The U.S.-led coalition confirmed the 15,000 casualty number but would not discuss it publicly. The deaths are tracked as part of daily battle damage assessments and coalition efforts to avoid civilian casualties. Aerial surveillance is used to assess the impact of airstrikes, including enemy casualties.