Speaking in the Indonesian capital today, Kerry told reporters that the administration understood ally Turkey's concerns about supplying the Kurds, who are linked to a Kurdish group that Ankara fiercely opposes.
But, he said the situation is such in the besieged town of Kobani that the resupplies were deemed absolutely necessary in a "crisis moment."
"Let me say very respectfully to our allies the Turks that we understand fully the fundamentals of their opposition and ours to any kind of terrorist group and particularly obviously the challenges they face with respect the PKK," Kerry said.
Kerry said the militants had chosen to "make this a ground battle, attacking a small group of people there who while they are an offshoot group of the folks that our friends the Turks oppose, they are valiantly fighting ISIL and we cannot take our eye off the prize here."
"It would be irresponsible of us, as well morally very difficult, to turn your back on a community fighting ISIL as hard as it is at this particular moment," he said.