J-10 fighter jets from the August 1st Aerobatics Team of the People's Liberation Army Air Force take off from a military base as they travel to Zhuhai for the upcoming China International Aviation & Aerospace Exhibition, in Tianjin municipality, Nove
J-10 fighter jets from the August 1st Aerobatics Team of the People's Liberation Army Air Force take off from a military base as they travel to Zhuhai for the upcoming China International Aviation & Aerospace Exhibition, in Tianjin municipality, November 5, 2014. The exhibition will be held in southern Chinese city of Zhuhai of Guangdong province from November 11 to 16. Picture taken November 5, 2014. Reuters

Russia has been at it again, flying over the Baltic Sea without a flight plan. On Monday, NATO said it scrambled at least two F-16 jets to intercept a Russian a supersonic Su-27 fighter jet.

NATO said that while the Russian military jet was flying over international waters, it was already hovering close to Latvian air space. This came a day after three Russian navy vessels including a Kilo-class submarine were spotted in international waters off the coast of Latvia.

NATO Baltic Air Policing QRA F16 jets on 17 NOV scrambled to intercept RU Armed Forces Su-27 over the Baltic Sea.

— NBS (@Latvijas_armija) November 17, 2014

Tom Nichols, a professor at the U.S. Naval War College and senior associate at the Carnegie Council on Ethics and International Affairs, told Business Insider that the increased Russian military air escapades were "not normal." He added such flights "clearly comes from the very top as an expression of Putin's foreign policy."

Armed Forces on 16NOV in LV EEZ 10nmi from territ. waters spotted RU Navy's Kilo-class submarine, corvette Stoikiy, and ship Viktor Koneckij

— NBS (@Latvijas_armija) November 17, 2014

Russian President Vladimir Putin, according to Bloomberg, told German TV network ARD on Sunday that its air and naval movements were harmless because they are happening "exclusively in the international waters and over international airspace." He likewise noted such posturings were routine.

Latvia, along with Estonia and Lithuania, were three former Soviet republics that joined NATO in 2004. NATO has been vigilantly ensuring their protection after Russia annexed the Crimean peninsula from Ukraine. NATO have been sending military planes and naval vessels in the Baltic Sea between St. Petersburg and Russia's Kaliningrad exclave.

The European Leadership Network, a security research group, said in a report that Russia is engaged in a "dangerous brinkmanship" toward NATO and Nordic nations. Since March, it had close to 40 incidents of incursions and close encounters with other aircraft carriers.

And when Mr Putin showed up during the G20 summit meetings in Australia, he was accompanied by no less than four Russian warships. Its presence was seen as a direct provocation to Australian Prime Minister Tony Abbott, who vowed to shirt-collar the Russian leader when they meet during the summit. It didn't happen, though.

"Certainly it is unusual for Russian naval elements to be in Australian waters," Mr Abbott said. "Unusual, not entirely unprecedented, but unusual ... Let's not forget that Russia has been much more militarily assertive in recent times."