British counterterrorism police investigating the stabbing of a journalist who works for a TV channel critical of the Iranian government said that three suspects had fled the country within hours of the attack.

Pouria Zeraati, a presenter at London-based Iran International, was stabbed in the leg Friday afternoon outside his home in London. Police said Zeraati, who has been released from a hospital, was attacked by two men who fled in a car driven by a third man.

“We have established that after abandoning the vehicle, the suspects traveled to Heathrow Airport and have left the U.K.,’’ Commander Dominic Murphy, head of the Metropolitan Police Counter Terrorism Command, said in a statement late Tuesday. “We are now working with international partners to establish further details.’’

Police said that while the motivation for the attack is still unclear, Zeraati’s occupation, together with recent threats to U.K.-based Iranian journalists, triggered a counterterrorism investigation. Iran International, a satellite news channel that broadcasts in Farsi, has previously received threats due to its coverage of Iran.

Mehdi Hosseini Matin, Iran’s charge d’affaires in the U.K., has said “we deny any link” to the incident.

Police say they have disrupted “a number” of plots to kill or kidnap people in the U.K. who were seen as enemies of the Iranian government. Officers are working with intelligence agencies to disrupt future plots and provide protection for the targeted organizations and individuals, police said.

Early last year, Iran International temporarily shut down its operations in London and moved to studios in Washington, D.C., after what it described as an escalation of “state-backed threats from Iran.” The station resumed operations at a new location in London last September.