Russia ordered its military on Saturday to draw up measures to increase the safety of the airspace over the Baltic Sea, after a string of incidents and near-misses that has ratcheted up tensions between NATO and Moscow.

Defence Minister Sergei Shoigu commanded the military to develop "a system of trust measures that would increase flight safety in the Baltic Sea region," a ministry statement said.

Russia's NATO-member Baltic neighbours have accused Moscow of regularly violating their airspace in recent months and flying with switched-off transponders, devices that allow radars to identify planes and prevent collisions.

Russian planes have also been accused of dangerous manoeuvres in the Baltic, with one particularly close call in April, when a Russian Sukhoi jet flew less than 50 feet (15 metres) from a US destroyer.

However, Moscow has also made its own accusations, notably against US spy planes invisible to Russian radars that then have to be visually identified by warplanes.

Russian President Vladimir Putin said Friday that NATO planes fly without transponders "twice as often" as Russian aircraft and promised to bring up the issue at an upcoming Russia-NATO council.

The defence minister is considering making the use of transponders compulsory if NATO countries take similar measures, the statement said.

Russia's military has focused heavily on the Baltics recently, with Shoigu announcing on Wednesday that the Baltic Fleet would be boosted by a new army corps.

Baltic Fleet commander Sergei Kravchuk and several other senior officers were sacked this week for "serious shortfalls in their duty," a rare major overhaul underscoring Moscow's growing attention to the region.