Poland and the Baltic states voiced concern Tuesday over Russia's missile defence plans in the Kaliningrad enclave bordering EU and NATO members Poland and Lithuania.

"We have to follow closely the changes in regional security because we are witnessing the deployment or announced deployment of new systems by Russia, in Kaliningrad and elsewhere," said Polish President Bronislaw Komorowski.

Komorowski met his counterparts from fellow EU and NATO members Estonia and Latvia on security ahead of a May 20-21 NATO summit in Chicago.

Moscow has stepped up its activity in the region in response to the US-backed anti-missile shield project in eastern Europe.

NATO has repeatedly assured that the missile shield is designed to protect Europe from threats from countries such as Iran, but Russia has slammed it as a potential threat to its own security.

Estonian President Toomas Hendrik Ilves said Tuesday the NATO-backed shield was a measure aimed against threats from "the south," namely from Iran.

"But missile defence has been used as an excuse to lead to a build-up of both missile and other installations precisely in our own region," he added.

Russia has announced a plan to deploy short-range Iskander missiles in Kaliningrad and Russian media recently said the country would also launch its S-400 Triumph mobile anti-aircraft and anti-missile defence system there.

"We would very much like the allies who have proposed this measure not to leave this area with less security (than before) thanks to an allied proposal to defend all of Europe against a potential Iranian attack," added Ilves.

Kaliningrad is an enclave controlled by Russia but sandwiched between Lithuania and Poland, which were part of Moscow's Cold War-era zone of influence.