The Pentagon chief is touring the Middle East in an effort to inspire regional support for the military campaign against Daesh.
While traveling to Incirlik air base in Turkey, Carter said Ankara needed to better control its border with Syria. In particular, he stated that the Turkish government must shore up a roughly 60-mile stretch of border that Daesh is believed to use for trade and transporting foreign fighters, he said.
"Turkey has an enormous role to play," Carter was quoted as saying by Reuters. "We appreciate what they're doing. We want them to do more."
According to Carter, that includes joining "in the air and the ground as appropriate. The single most important contribution that their geography makes necessary is the control of their own border."
Incirlik air base has become crucial in the US-led coalition’s air campaign against Daesh. Around 45 of the 59 aircraft using the base are from the United States. The number of American personnel at Incirlik has been increased to 1,300 from around 300 in July, Reuters reported.
Carter's visit to Incirik comes amid heightened tensions between Turkey and Iraq over Ankara’s deployment of troops to a base near the northern Iraqi city of Mosul. On Monday, Turkish troops began leaving their camp in Iraq and moving north.
Carter has asked allies for more contributions to the anti-Daesh campaign, which he said could include strike aircraft, intelligence flights, transport aircraft, border control and troop training.
On Tuesday, Saudi Arabia announced the formation of a 34-nation Muslim military coalition to combat terrorism.
Carter said Sunni Gulf Arab countries could encourage and help Sunni Muslim communities living in areas controlled by Daesh, a hardline Sunni group, to resist their rule.
"That's something that obviously they can do that it's harder for other countries to do," he said.
"Different countries can make different kinds of contributions and over this trip and in the subsequent weeks and months I'll be asking them each to make the strongest, most robust possible contribution that they can."