NATO's Secretary-General Jens Stoltenberg urged Austria and Turkey on Friday to resolve a diplomatic dispute that has led to some cooperation programmers being blocked.

Austria, which is not a NATO member but cooperates with the alliance, led calls last year to halt Turkey's European Union accession talks. Vienna has also spoken out against Turkish politicians holding rallies in European countries.

Turkey, a NATO ally, has withdrawn from some alliance cooperation, saying the move is aimed only at Austria.

"It is a very unfortunate situation and it means some cooperation programs can't be launched ... We strongly urge them to solve it, so that it won't have negative consequences for the cooperation," Stoltenberg told reporters during a visit to the Danish capital Copenhagen.