NATO Secretary General Jaap de Hoop Scheffer said Thursday that Russia has agreed to resume cooperation with the alliance on a key theater missile defense (TMD) program.

"The Russian Federation has agreed to participate in an important, so-called computer-assisted exercise on theater missile defense, which will be held in Germany in a few weeks' time," the NATO chief told reporters at an informal meeting of defense ministers in the Dutch seaside resort of Noordwijk.

Russia scrapped the exercise at the 11th hour, apparently to show anger at a US plan to deploy a ballistic missile shield in Poland and the Czech Republic.

Washington claims that the site is to fend off potential long-range missile threat from Iran. But Russia says it is actually designed to weaken Moscow's missile deterrence.

NATO and Russia have been working on TMD cooperation for years to create the conditions for the two sides to conduct joint TMD operations.

Theater missile defense is aimed at short-and medium-range missile attacks.

NATO defense ministers and their Russian counterpart, Anato ly Serdyukov, held informal talks on Thursday, the atmosphere of which, De Hoop Scheffer said, was positive and constructive.

But the two sides failed to make progress on the issues of missile defense, Kosovo and the Conventional Forces in Europe (CFE) Treaty.

De Hoop Scheffer on Thursday warned against a possible "irreversible" Russian move on the CFE treaty.

"The allies and I would deplore very much if the Russian Federation would at a certain stage decide to suspend or to leave the CFE treaty," he told reporters, referring to news that the Russia Duma -- the lower house of parliament -- will begin discussing the fate of the CFE treaty.

Russian President Vladimir Putin signed a decree suspending Russia's participation in the CFE treaty in July, which needed the approval of the State Duma.

The CFE treaty aims to maintain military balance in Europe by setting limits on key categories of conventional military equipment for NATO countries and those of the rival Warsaw Pact. It was signed in 1990 and an adapted treaty was agreed upon in 1999.

So far only Russia, Belarus, Kazakhstan and Ukraine have ratified the 1999 treaty. NATO countries have refused to do so, insisting that Russia must first fulfill the so-called "Istanbul obligations" to withdraw Russian troops from Moldova and Georgia.

(Xinhua News Agency October 26, 2007)