France will deploy four Mirage 2000 fighter planes to the Baltic states in September for an air policing mission in line with NATO's initiative to boost defence in states bordering Russia, the French army announced Thursday.

"We are going to take part for the sixth time in the Baltic Air Policing mission," from September through December, army spokesman colonel Gilles Jaron said.

France is the second country to contribute to the air policing effort after Germany, the army added.

Air force spokesman colonel Olivier Celo said "this mission is intended to enforce respect for the air space of the three Baltic states" ---- Lithuania, Latvia and Estonia which joined NATO in 2004.

On previous missions, French planes made some 36 interceptions, with Russia having increased in the past few years its over flights by bombers in the region, considered an aggressive move near NATO countries, Celo said.

NATO announced last week that it would deploy four battalions to the Baltic nations and Poland to counter a more assertive Russia, ahead of a landmark summit in Warsaw on July 8-9.

All four countries were once ruled from Moscow and remain deeply suspicious of Russia's intentions, especially after Moscow's 2014 annexation of Crimea from Ukraine.

Russia bitterly opposes NATO's expansion into its Soviet-era satellites and last month said it would create three new divisions in its southwest region to meet what it described as a dangerous military build-up along its borders.