A Russian fighter jet came within 10ft of a US spy plane over the Black Sea in a manoeuvre branded "unsafe" by the Pentagon.

Defence officials claimed the Russian Su-27 fighter flew dangerously close to the US Navy P-8A Poseidon aircraft for 19 minutes on Wednesday as it was conducting routine operations in international airspace.

Moscow has insisted the intercept was performed "in strict accordance with international flight rules", with a defence ministry spokesman alleging the US aircraft had approached Russia's southern border twice.

Major General Igor Konashenkov said the US spy plane's transponders were switched off, meaning the aircraft could not be identified without close visual confirmation.

The intercept is likely to increase tensions between the US and Russia, with both countries currently at odds over Ukraine and the civil war in Syria.


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Pentagon spokesman Captain Jeff Davis said most interactions with Russian units in the area were safe and professional, but warned flying within 10ft of another aircraft "has the potential to unnecessarily escalate tensions, and could result in a miscalculation or accident".

US defence secretary Ash Carter added: "Russia appears driven by misguided ambitions and misplaced fears.

"It lashes out, alleging that it fears for its own viability and future, even though no nation - not the United States, not the United Kingdom - seeks to defeat it or constrain its potential."

There have been a number of similar spats between the US and Russia over military manoeuvres this year.

In April, US officials claimed that two Russian warplanes flew "simulated attack profiles" near an American guided missile destroyer - coming so close to the USS Donald Cook that they created a "wake in the water".

Later that month, Moscow denied acting in an "unsafe and professional" manner after reportedly performing a high-speed barrel role as it intercepted a US aircraft - coming within about 100ft (30m) of the plane.