Multiple U.S.-led airstrikes have struck near the northern Syrian town of Kobani, where Kurdish fighters are battling to hold off an advance by Islamic State militants.
The U.S. military said eight airstrikes carried out with the help of Jordan hit IS targets Wednesday, and that the Kurds continue to control most Kobani, also known as Ayn al-Arab.
U.S. fighters also struck multiple militant targets in Iraq.
Australia's military said Thursday that its warplanes conducted their first airstrikes against the Islamic State group in Iraq overnight.
Australian Prime Minister Tony Abbott stressed the need to help the Iraqi government battle militants who kill everyone who does not share their "narrow, divisive and sectarian ideology."
"This is a death cult that has declared war on the world. It's got nothing whatsoever to do with religion. It's got nothing whatsoever to do with the freedom of oppressed people. It is a group which has declared war on the world, which is killing without compunction," said Abbott.
Meanwhile, the United States is sending retired General John Allen and Ambassador Brett McGurk to Turkey for two days of talks with officials to push for action against the Islamic State group.
Turkey's parliament has authorized military action in Syria and Iraq, but Turkish forces have not carried out any actions against the militants.
NATO Secretary General Jens Stoltenberg is also due in Syria Thursday to meet with a group of officials, including President Recep Tayyip Erdogan and Prime Minister Ahmet Davutoglu.
White House spokesman Josh Earnest said Wednesday that the U.S. military is limited in what it can do to help Kurdish fighters in Kobani because there is not the same kind of ground operation in Syria as there has been in Iraq, where airstrikes have helped Iraqi and Kurdish forces.
Secretary of State John Kerry said the idea of a buffer zone along the border is an idea worth looking at closely. France and Britain also have shown support for the idea.
But, the White House said, it is not something under consideration right now.