MOSCOW (AP) — Russia's foreign minister has rejected the conclusion by a British judge that former KGB officer Alexander Litvinenko had been poisoned by two men acting at the behest of Russia's spy agency as a "show" lacking substance.

Minister Sergey Lavrov said Tuesday that Judge Robert Owen's conclusion was based on testimony of hand-picked witnesses who he said lacked objectivity and classified testimony. Lavrov added British officials' statements on the issue could be viewed as slander.

Owen said he was certain two Russians with links to the security services had given Litvinenko tea containing a fatal dose of radioactive polonium-210 at a London hotel in 2006. He said there was a "strong probability" the poisoning came under the direction of Russia's FSB spy agency and President Vladimir Putin probably approved it.