New Delhi, March 31 -- Russia on Monday expelled a British diplomat over accusations of spying that were rejected as "complete nonsense" by the U.K., a second such move this year that comes as tensions spiral between Moscow and the West.

Russia's Federal Security Service (FSB), the country's top domestic security and counterintelligence agency, said in a statement that the diplomat was "carrying out intelligence and subversive activities that threaten ⁠the security of the Russian Federation."

The FSB charged that the diplomat had sought to gather "sensitive information" about the Russian economy in "unofficial meetings" with Russian experts, without providing further details. It said he was ordered to leave Russia within two weeks...