NATO Secretary-General Jens Stoltenberg praised on Saturday Turkey's contribution to security in Europe.

"NATO would undoubtedly be weaker without Turkey," Stoltenberg told the German Welt am Sonntag newspaper, adding that Turkey fulfilled all of its obligations and made important contributions to NATO operations.

Stoltenberg labeled Turkey a "key country" for both NATO's and Europe's security and stability.He underlined Turkey's "huge importance" in the fight against Daesh due to its geographical location near crisis-hit Syria and Iraq, as well as its military capabilities.

The NATO secretary-general also stressed that Turkey is a key player in relations between the alliance and Russia, as it is bordering the strategically important Black Sea region.

Stoltenberg said it was important that the alliance showed unity despite different views on certain political issues, and agreed on NATO's core task to protect and defend its member states.

"We should especially focus on what unites us," said Stoltenberg.

NATO is one of the major political and military alliances in the world with 28 member states from Europe and North America.It mainly focuses on the protection and defense of the member states' territory and population, while also taking action when needed to uphold international peace and security.