MOSCOW (Reuters) - Russia's FSB security service on Tuesday accused Ukrainian military intelligence of organising an attack on a gas pipeline on Russian-annexed Crimea after Moscow arrested a Crimean Tatar leader over the incident.

       The FSB said Ukraine's GUR military intelligence service and the Mejlis, the outlawed representative body of the Crimean Tatars, had conspired to blow up a gas pipeline on Aug. 23 outside the city of Simferopol.

       There was no immediate reaction from Ukraine.

       Russia annexed Crimea from Ukraine in March 2014, drawing Western sanctions. The West and most of the world recognise the Black Sea peninsula as Ukrainian, and Kyiv wants the territory returned.

       On Monday, a court in Crimea ordered Nariman Dzhelyalov, ex-deputy chairman of the Mejlis, to be held in custody for two months over the pipeline incident.

       The FSB said in a statement that the perpetrators had been promised a payment of around $2,000 by Ukraine's military intelligence.

       "It has been established the sabotage was organised by a branch of the Ukrainian Defence Ministry's Main Intelligence Directorate in the city of Kherson... with the participation of the Mejlis...," the FSB said.

       It said it had launched a criminal case into sabotage, an offence that can carry a prison sentence of up to 15 years.

       Russia banned the Mejlis in 2016, branding it an "extremist" body. Many Crimean Tatars were opposed to the Russian annexation of the peninsula.

       The United States, an ally of Ukraine, has accused Moscow of targeting the Mejlis and its leadership and called for Dzhelyalov's release.

       (Reporting by Gabrielle Tétrault-Farber; Editing by Gareth Jones)