The U.S. military has airdropped weapons, ammunition and medical supplies to Kurdish fighters in the Syrian city of Kobani to beef up the defense against ISIS forces, the Pentagon said.

"The aircraft delivered (items) that were provided by Kurdish authorities in Iraq and intended to enable continued resistance against ISIL's attempts to overtake Kobani," the U.S. Central Command said Sunday.

(The administration refers to the group as ISIL, the acronym for "Islamic State of Iraq and the Levant." CNN refers to it as ISIS; the group recently started calling itself the Islamic State.)

The move was partly humanitarian but also aimed at shoring up the Kurdish defenders of Kobani, senior Obama administration officials said -- acknowledging it was a shift in the administration's tactics to date.

"This is a part of the President's larger strategy to degrade and destroy ISIL wherever they are," one official said.

The gear was delivered by three C-130 cargo planes and appeared to have been received on the ground by Kurdish fighters, senior Obama administration officials.

There have been reports that ISIS may have anti-aircraft missiles, but the officials said they had no evidence to back those reports and that the cargo planes flew in unescorted.

Kobani, a Kurdish town on the Syrian-Turkish border, now is the scene of an unrelenting battle.

On Sunday, the brief moments of calm were punctuated by sounds of firing from both sides.

ISIS has shelled the city at least 16 times, sources say, while coalition planes fly low overhead.

The U.S. has generally downplayed the importance of Kobani as a key city in the battle against the militants.

However, if ISIS takes Kobani, that would mean it would control land between the northern Syrian city of Raqqa and Turkey -- about 100 kilometers (60 miles).

The Islamic State in Iraq and Syria took control of Raqqa last year. ISIS uses the once-liberal city as a kind of headquarters where it applies its hardline interpretation of Islamic law, terrorizing the population.

With the help of airstrikes from an international coalition led by the United States, Kurdish and Iraqi forces are now focused on pushing ISIS back from its relentless attempt to take Kobani.

(CNN)