Nato dispatched fighter jets to intercept a Russian IL-20 military surveillance plane over the Baltic Sea yesterday, the third such incident this week.
The CF-18 Hornet fighters, Canadian jets based in Lithuania, confronted the Russian aircraft over international waters near Latvia's border, the Latvian army said on Twitter.
It said a Russian navy tanker was also observed 11.6 nautical miles from Latvian waters yesterday, the vessel's second sighting near the maritime border in the past three days.
The encounters have added to the growing strain between Russia and the military alliance over the conflict in Ukraine. Russian warplanes and ships have increased their activity across the Baltic Sea from St Petersburg to the Kaliningrad exclave that borders Nato members Poland and Lithuania.
The alliance pledged in September to bolster the defences of frontline states in eastern Europe in response to what it said was Russian involvement in Ukraine.
Nato interceptions of Russian military planes over the Baltic have more than doubled from last year, the news service BNS reported.
President Vladimir Putin said on Sunday that Russian planes and ships do not violate European borders and that military exercises take place "exclusively in international waters and over international airspace".
- Putin greeted the new US ambassador to Russia yesterday with a demand for Washington to treat Moscow as an equal partner and stay out of its internal affairs.
The new envoy, John Tefft, said that he wanted to strengthen "people-to-people" ties but there were serious differences over Ukraine.
The US and the EU imposed sanctions on Moscow after its annexation of the Crimea peninsula from Ukraine and over its backing for separatists in the east.
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