The United States has sharply increased the number of airstrikes against Islamic State militants in the besieged Syrian city of Kobani — aided by information provided by Kurdish fighters, American officials said Wednesday. A Pentagon spokesman said that the airstrikes had killed “several hundred” Islamic State fighters. Kurdish officials said the intensified attacks had allowed them to regain territory and push the militants back on several fronts, after fears rose last week that the city would be overrun. Yet in a sign of the perils of the intensified bombing campaign, five Kurdish fighters were killed late Tuesday — possibly because they had advanced too close to one of the airstrikes. A spokesman for the United States Central Command, Maj. Curtis J. Kellogg, said American officials had “no evidence indicating Kurdish fighters were killed in a coalition airstrike last night. Regardless, we take such reports seriously and will […]