The U.S. and Dutch militaries also carried out three airstrikes against Islamic State targets in Iraq near Tal Afar and Hit on Friday and Saturday, Central Command said in a statement.

Additionally, U.S. forces "conducted multiple airdrops to help resupply Iraqi security forces at the request of the Government of Iraq," it said, adding the supplies of food, water and ammunition were dropped around Baiji, the site of Iraq's largest oil refinery.

The air attacks near Kobani hit an Islamic State fighting position and two small units, damaged a command-and-control facility and destroyed three trucks, the statement said.

A U.N. official said on Friday thousands of people most likely will be massacred if Kobani falls to Islamic State, which has seized large parts of Syria and Iraq.

In Iraq, an air strike north of Tal Afar struck a small Islamic State unit and destroyed an armed vehicle, while two small units of the group were targeted in two strikes northwest of Hit, the statement added.

In multiple airdrops near Baiji, U.S. aircraft delivered 8 tons of ammunition, more than 2,000 gallons (7,800 litres) of water and more than 7,300 halal meals, the statement said.

It said Iraqi forces control Baiji, 110 miles (180 km) north of Baghdad, but Islamic State "continues to conduct operations" in the area.

An Iraqi army helicopter crashed near the Baiji oil refinery on Wednesday. Islamic State claimed the group shot down the aircraft, according to the SITE monitoring service.