LONDON - British Typhoon fighter jets were scrambled to intercept two Russian Bear long-range bombers which had flown close to UK airspace, Britain's Ministry of Defence (MoD) said on Thursday.The Russian planes were detected flying over the Channel, south of England, on Wednesday and typhoons were launched from Royal Air Force (RAF) bases at Lossiemouth in Scotland and Coningsby in eastern England, the MoD said."The Russian planes were escorted by the RAF until they were out of the UK area of interest. At no time did the Russian military aircraft cross into UK sovereign airspace," the Ministry of Defence said in a statement.Last year, NATO conducted more than 100 intercepts of Russian aircraft, about three times as many as in 2013, amid sharply increased tensions between the West and Moscow over the Ukraine crisis.Elizabeth Quintana, a senior research fellow at defense think-tank the Royal United Services Institute said Wednesday's incident was unusual however, and could be linked to Britain beginning an inquiry into the death nine years ago in London of Kremlin critic and ex-KGB spy Alexander Litvinenko."Normally Russian Bears come past Norway and down the North Sea. It could have been used to probe the RAF speed of reaction south," she told the Daily Mail newspaper."Flying any military aircraft in or close to the sovereign airspace of another country signals displeasure or at worst aggression."