The Aravot newspaper said the decision was made after a meeting last Wednesday in Brussels between Azerbaijani President Ilham Aliyev and NATO Secretary General Jaap de Hoop Scheffer at which the NATO chief supported the territorial integrity of Azerbaijan.
Relations have been tense for more than two decades between Armenia and Azerbaijan over Nagorny Karabakh, a region in Azerbaijan with a largely Armenian population. The region declared its independence in a 1991 after a referendum boycotted by local Azerbaijanis. The ensuing conflict claimed some 35,000 lives before a ceasefire was signed in 1994. The area technically remains part of Azerbaijan, but has its own de facto government.
However, Armenian authorities have not yet officially confirmed the country's withdrawal from the NATO exercises. Armenian Foreign Ministry told RIA Novosti on Tuesday that the situation "was still unclear."
The Cooperative Longbow/Cooperative Lancer 2009 command-and-staff exercise, which Russia has criticized as unhelpful in the wake of last summer's armed conflict between Russia and Georgia over South Ossetia, is scheduled for May 6-June 1.
According to NATO, the drills are aimed at improving interoperability between NATO and partner countries, within the framework of Partnership for Peace, Mediterranean Dialogue and Istanbul Cooperation Initiative programs, and will not involve any light or heavy weaponry.
Over 1,300 troops from 19 NATO member or ally states were originally scheduled to participate, but Kazakhstan, Latvia, Estonia, Moldova and Serbia have already withdrawn.
Meanwhile, Azerbaijan confirmed on May 1 its participation in the NATO-led exercises, and stressed the country's commitment to relations with NATO and its active participation in the Individual Partnership Action Plan.