MOSCOW (AFP) - Russia's FSB security service on Thursday (March 31) said it had detained an alleged CIA-trained Ukrainian intelligence officer who was trying to become a triple agent, and would deport him.

"On March 26 on Russian territory, an employee of the counterespionage department of the SBU security service of Ukraine, lieutenant-colonel Yury Ivanchenko, was detained," the FSB said in a statement.

"Ahead of his arrival in Russia, the FSB received information that the SBU and the CIA prepared Ivanchenko to take part in an operation to be recruited by the FSB by offering them his services," the statement said.

"As the actions of the foreigner did not damage the security of Russia, he will be deported from Ukraine and be banned from entering Russia," it said.

Russia and Ukraine are locked in a bitter feud over Moscow's seizure of the Crimean peninsula from Kiev in 2014 and the fuelling of a separatist uprising in the east of the country.

The Ukraine crisis has also plunged relations between Moscow and the West to their worst point since the end of the Cold War, with the US and EU slapping sanctions on Russia.

Kiev says Moscow is currently holding around a dozen Ukrainians as political prisoners, including pilot Nadiya Savchenko who was sentenced to 22 years in jail this month over the killing of two Russian journalists in east Ukraine.

Ukrainian authorities are pushing for a prisoner swap involving Savchenko and two Russians accused of being army officers who were captured while fighting with rebels and are currently on trial in Kiev.