MOSCOW, March 3. /TASS/. Russia's biggest gas producer Gazprom began at Stockholm's arbitration tribunal the procedure of terminating contracts on gas supplies and transit with Naftogaz Ukrainy, Gazprom's Deputy Chairman of the Board Alexander Medvedev told reporters on Saturday.

"We have begun the procedure to terminate contracts with Naftogaz Ukrainy," he said. "The new case at the Stockholm arbitration court hearing would be considered by other arbitrators".