Turkey's top diplomat in Afghanistan has been appointed as NATO's senior representative in the war-torn country, the Turkish foreign ministry and the military alliance said Monday.

NATO Secretary General Jens Stoltenberg has appointed Ambassador Ismail Aramaz as the next senior civilian representative in Afghanistan and he is expected to take up his new post early next year, NATO said in a press release.

NATO head Jens Stoltenberg called on Russia Friday to withdraw its troops from Ukraine as the country prepares for key national elections which pro-Moscow rebels plan to prevent in areas they control.

Stoltenberg, who took office last month with the crisis top of his agenda, said Russia's continued presence and support for the rebels violated international law, as well as  Ukraine's sovereignty and territorial integrity.

NATO leaders agreed Friday to set up a rapid reaction force as part of efforts to reassure allies rattled by the Ukraine crisis and rising Islamic extremism, alliance head Anders Fogh Rasmussen said.

As a result, NATO will be able to "maintain a continuous presence... in eastern parts of the alliance on a rotational basis," Rasmussen said, denouncing Russian aggression in Ukraine.

NATO chief Anders Fogh Rasmussen expressed concern on Wednesday that Russian President Vladimir Putin's ambition went "beyond Ukraine," where he is accused of stoking a bloody rebellion by pro-Kremlin separatists.

NATO chief Anders Fogh Rasmussen said in an interview published Sunday that the alliance would draw up new defense plans in the face of "Russia's aggression" against Ukraine, urging members to up their military spending.

Echoing comments by British Prime Minister David Cameron, Rasmussen told French regional newspaper Midi Libre that "Russia's aggression was a warning and created a new security situation in Europe."

NATO on Monday launched one of its largest military maneuvers in the Baltic states since tensions spiked with neighboring Russia over its annexation of Ukraine's Crimean peninsula.

Around 4,700 troops and 800 military vehicles from 10 countries including Britain, Canada and the United States are participating in the Saber Strike exercises near the Latvian capital Riga.  

Russia on Monday accused the European Union of putting pressure on Bulgaria to suspend work on a key Kremlin-backed gas pipeline, and said eastward expansion by NATO was "counterproductive".

Foreign Minister Sergei Lavrov said EU member state Bulgaria's move to halt work on the South Stream gas pipeline suggested the bloc was seeking revenge over the Ukraine crisis.

Russia has withdrawn most of the some 40,000 troops it had massed on the Ukraine border and those remaining are preparing to pull out, a NATO military official said Tuesday.

The official, who asked not to be named, said NATO continued to see Russian troop activity near the border but "the majority of troops have now pulled back."

NATO and Russia had a "very frank" exchange of views on the Ukraine crisis Monday but found no common ground in the first such meeting since Moscow annexed Crimea, officials said.

"I can say it was a very frank exchange of views," alliance spokeswoman Oana Lungescu said after a meeting of the NATO-Russia Council which groups the 28 member state ambassadors with their Russian counterpart.

The United States has sent its top general in Europe back to the continent early, amid what the Pentagon on Sunday called Russia's "lack of transparency" over the Ukraine crisis.

General Philip Breedlove, NATO's supreme allied commander Europe and the U.S. military's European Command chief, returned to Europe on Saturday from a visit in Washington, where he had been due to testify before Congress.