NATO Secretary-General Jens Stoltenberg has said the alliance must prepare for further challenges after a "black year" of Russian intervention in Ukraine and terror attacks on Europe's streets.
Stoltenberg, who unveiled NATO's 2014 annual report in Brussels, said the alliance will deploy small units in six eastern European nations to help coordinate a "spearhead force" set up in response to Russia's actions in Ukraine.
Stoltenberg said the units in Estonia, Latvia, Lithuania, Poland, Bulgaria, and Romania will be the first of their kind there.
The forward units will be made up of only a few dozen troops. They will plan and organize military exercises, and provide command and control for any reinforcements the force might require.
Defense ministers from the 28-nation military alliance will discuss the full force, which should be able to react quickly to any hot spots in Europe, when they meet on February 5.
Stoltenberg said countries responsible for providing the several thousand troops should be known next week.
Norway, Germany, and the Netherlands have said they are ready to contribute.
The quick reaction force was agreed upon by NATO leaders at a summit in September in Wales.
The NATO chief said the force would help cope with a "fundamentally changed" security environment.
Stoltenberg said "2014 was not a good year for European security. In fact it was a black year."
He said Russia's interference in Ukraine was a key problem for European security.
He also urged member states to keep commitments made at the summit to boost defense spending to the equivalent of 2 percent of annual economic output within 10 years.
Russia had economic problems too, Stoltenberg noted, but that had not prevented Moscow from beefing up its military.
He said "we have seen Russia over a period of many years increase their investment in defense despite financial problems."
"We have seen that Russia is ready to use force," he added, citing Ukraine, and Georgia, and Moldova, all former Soviet states which have turned to the West in defiance of Moscow.
The NATO chief said the alliance was "supporting Georgia, modernizing, reforming their armed forces."
He added that the alliance was setting up a training center with NATO trainers in Georgia.
Asked about possible contacts with Russia to reduce tensions, Stoltenberg said he was likely to meet Foreign Minister Sergei Lavrov on the sidelines of the Munich Security Conference next week, even though NATO has suspended its practical cooperation with Russia.
Stoltenberg also warned of the threat from Islamic State militants and other extremist groups on NATO's borders, especially after the Paris attacks earlier this month in which "homegrown" jihadists killed 17 people.