NATO has ruled out sending ground troops to fight against Islamic State militants in Syria, NATO General Secretary Jens Stoltenberg told a Swiss newspaper, stressing the need to bolster local forces in the conflict, Reuters reports.

"That is not on the agenda of the coalition and the NATO allies," he told the Tages-Anzeiger paper when asked about dispatching ground forces to accompany air strikes.

"The United States has a limited number of special forces. In the foreground, however, is strengthening local forces. This is not easy, but it's the only option," he added.

Stoltenberg stressed that the conflict was not a war between the West and the Islamic world, but rather against "extremism and terrorism".

"Muslims are on the front line in this war. Most victims are Muslims, and most of those who fight against the IS are Muslims. We cannot carry on this struggle for them," he said, according to Reuters.

Stoltenberg pointed out that NATO would help Turkey improve its air defenses after Turkey shot down a Russian military jet last month. The alliance will adopt a package of measures for Turkey before Christmas, he added.

He emphasized the need to calm the standoff with Russia after the plane was shot down.

"Now it is important to de-escalate and to develop mechanisms to prevent similar incidents in the future. We see a significant build-up of the Russian military presence from the far north to the Mediterranean. There, too, we need to avoid similar incidents such as in Turkey," he said.