U.S. Defense Secretary Chuck Hagel said Thursday that the key military assistance the United States would like to get from Turkey would be access to the Turkish air base at Incirlik and an agreement to help train and equip the moderate Syrian forces.

Hagel said U.S. officials are raising those issues with Turkish leaders in discussions this week. While Ankara's persistent request for the U.S. to set up a safe zone along Turkey's border with Syria is not "actively being considered," he said, American leaders are open to a discussion about it.

The defense secretary said Turkey has military capabilities that would be valuable in the fight against the Islamic State militants. The U.S. would like to be able to base various aircraft at the air base near the Syrian border, he said.

Hagel spoke to reporters on his plane as he began a six-day, three-country trip to South America. His first stop is Colombia, and he will also go to Chile and Peru, where he will attend a conference of defense ministers from the Americas.

His trip comes as the U.S. works with coalition partners to slow the advances of Islamic State militants in Syria and Iraq, and as the U.S. military ramps up its troop deployments to Liberia to build medical facilities and help in the fight against Ebola.

U.S. leaders have been urging Turkey to get more involved in the battle against the Islamic extremists who have stormed across Iraq and Syria and taken control of large amounts of territory near Turkey's border. U.S. and coalition forces have been launching airstrikes near the Syrian border town of Kobani, which officials believe could fall to the militants.

Military leaders are very aware of concerns that if Turkish forces face off against Islamic State militants across the border in Syria, they also could target the Kurdish fighters who are battling the extremists. The Kurdish fighting force in Syria is linked to an opposition movement that has sought greater autonomy from Ankara for Kurds inside Turkey.

The moderate rebels have been fighting to topple Syrian President Bashar Assad — a goal for the U.S. As part of that effort, President Barack Obama authorized the U.S. to train and equip the rebels, also in the hopes that they could form a more cohesive fighting force against the Islamic State militants.

That training has not yet begun because officials need to first select and vet the rebels for the program.

The military assault against the Islamic State militants around Kobani has escalated in recent days. Since Monday the U.S. and coalition partners have launched airstrikes at more than 30 locations around the town. U.S. Central Command, which is overseeing the military campaign, said it continues to monitor the situation in Kobani.