KIEV, June 16 - Ukraine on Monday expressed "major concerns" over Russia's move to suspend participation in a landmark arms controls treaty in Europe, possibly resulting in Moscow sending more combat troops to its borders.

"Of course, this creates major concerns for Ukraine as far as providing for our national security," Oleksandr Chaliy, deputy chief of staff at the office of President Viktor Yushchenko, said.

President Vladimir Putin on Friday suspended Russia's participation in the Conventional Forces in Europe treaty due to "extraordinary circumstances which affect the security of the Russian Federation and require immediate measures."

Chaliy said Kiev will seek consultations with Russia and NATO nations in the near future in order to secure assurances that would provide for Ukraine's national security.

Eduard Shevardnadze, who as Soviet foreign minister helped to seal the 1990 CFE treaty, called Russia's withdrawal from it the first step towards a new Cold War.

The treaty, between Russia and NATO members, was signed in 1990 and amended in 1999 to reflect changes since the breakup of the Soviet Union, adding the requirement that Moscow withdraw troops from the former Soviet republics of Moldova and Georgia.

Russia has ratified the amended version, but the United States and other NATO members have refused to do so until Russia completely withdraws, causing irritation in Moscow.

NATO said on Monday it was very concerned at Russia's decision to suspend participation in the treaty.

"The announcement by the Russian Federation is deeply disappointing. The Allies are very concerned by this unilateral decision," the 26-nation Western military alliance said.

The development is the second major deterioration of relations between Russia and the West over the past month. Putin said earlier this month Russia would target its nuclear missiles at Europe if the U.S. goes ahead with plans to build a missile interceptor complex in Poland and the Czech Republic.

The deterioration will probably trigger calls within Ukraine for faster integration with NATO. Yushchenko, a pro-Western leader, has called for faster accession to NATO.

The treaty established limitations on countries' deployment of tanks, armored combat vehicles, artillery, attack helicopters and combat aircraft in Europe. Withdrawal from the treaty would allow Moscow to build up forces near its borders.

Ukraine, which has a huge common border with Russia, fears Russia may seek to deploy more troops near its border, directly threatening the country's national security. (tl/ez)