Five planes monitored in radiation probe

LONDON (Reuters) - Britain is monitoring five planes for radiation in an ever widening probe into the poisoning of a former Russian spy that has heightened tensions with Moscow.

Home Secretary John Reid told parliament on Thursday that radioactive traces had been found at 12 out of 24 locations being checked by police and pledged there would be no political barriers to the probe.

The Kremlin and Russia's foreign spy service have denied any involvement in the death of Alexander Litvinenko, a former Russian spy who became an outspoken critic of Russian President Vladimir Putin.

Litvinenko, who became a British citizen while living in London, died in the capital a week ago after being poisoned with radioactive polonium 210.