"In the nearest future the NATO general secretary is due to visit here, and I hope that he will inform us about plans to expand the alliance's military presence into the Baltic states," Interfax quoted Ivanov as saying.

At NATO headquarters in Brussels, a senior official denied that Moscow had been left in the dark over plans for Estonia, Latvia and Lithuania, which are due to formally join the alliance on April 2.

"Russia has been kept fully informed of what NATO's intentions are," said the official, speaking on condition of anonymity.

He said Moscow was aware of plans for what he termed a "low-level deployment to give all NATO nations air protection".

Ivanov repeated warnings that Russia reserved the right to take retaliatory steps to protect its security.

"We are following this situation closely and if these actions violate the Conventional Forces in Europe (CFE) treaty, we will have the right to take measures in the interests of our own security," he said.

In 1999, 30 countries including the United States and Russia signed an updated version of the 1990 CFE treaty at a meeting in Istanbul limiting conventional forces in Europe. The pact is designed to eliminate the risk of surprise attacks.

The NATO official in Brussels said the warplanes plan would not violate the CFE treaty.

Contacted by AFP, the NATO representative office in Moscow confirmed that Scheffer was scheduled to visit Russia "in the near future" but said the exact date was still under discussion.

Russia has shown increasing irritation at NATO's plans to provide an air defence umbrella for the three Baltic states.

Denmark is contemplating sending four F-16 fighter jets to patrol Estonia, Latvia or Lithuania, a Danish military spokesman said last week.

It is also considering sending a mobile radar station and about 100 soldiers to the future NATO allies. Belgium's defence minister, Andrew Flahaut, has said Brussels could replace the Danish deployment at a later, unspecified date.

Ivanov urged NATO in February not to put new military facilities in Poland and the Baltics, warning that Moscow could boost its military presence in its Kaliningrad enclave between Poland and the Baltics.

Russia has watched warily as the Atlantic alliance has expanded eastwards ever closer to its borders following the collapse of the Soviet Union in 1991.

The bloc already includes former Soviet satellites the Czech Republic, Hungary and Poland which joined in 1999.

In April NATO also takes in four other former Warsaw Pact countries -- Bulgaria, Romania, Slovakia and Slovenia.

WAR.WIRE