A U.S.-led air campaign against Islamic State fighters near the Syria-Turkey border town of Kobani has killed hundreds of them, Pentagon press secretary Rear Adm. John Kirby said at a briefing Wednesday. Despite the strikes, the city could still fall to Islamic State forces, Kirby said

The deadly attack comes after a weekslong battle between Islamic State fighters, also known as ISIS or ISIL, and Kobani's Kurdish population over control of the strategic area. The coalition air campaign has tightened its focus in recent days after closer coordination with Kurdish ground forces in Kobani. U.S. warplanes conducted at least 21 airstrikes on Monday and Tuesday.

"We are striking the targets around Kobani for humanitarian purposes. I'd be very reluctant to attempt to assign something, a term like 'a strategic target,' or 'a strategic outcome,'" Gen. John Allen said Wednesday, according to Reuters. "Given the circumstances associated with the defense of that town, there was a need for additional fire support to go in to try to relieve the defenders and to buy some white space, ultimately, for the reorganization on the ground. ... We have picked up the tempo and the intensity of the airstrikes in order to provide that white space."

Kurdish officials said the main Syrian Kurdish force, the YPG, relayed coordinates of Islamic State group forces to coalition operators. The Islamic State captured about half of the city, which has largely been abandoned by its residents, in recent days. Around 200,000 people from Kobani and environs have fled in the wake of the Islamic State group's offensive.

U.S. President Barack Obama said his administration was “deeply concerned” about Kobani in a meeting with coalition military leaders on Tuesday and reiterated the U.S. position that a more “capable” ground force is needed to save the border town.