LONDON — British counterterrorism police are investigating the stabbing of an Iranian television presenter outside his home in London as concern grows over threats to a Farsi-language satellite news channel long critical of Iran’s theocratic government.

Pouria Zeraati, a presenter at London-based Iran International, was stabbed in the leg Friday afternoon and is in stable condition at a hospital, the station said. His condition is not believed to be life-threatening.