Three people – including a police officer – have been stabbed by a man wielding a knife at Manchester Victoria railway station.
A man and woman in their 50s were attacked at about 20:50 GMT, Greater Manchester Police said.
A British Transport Police officer was stabbed in the shoulder. The victims’ injuries were described as “serious” but not life-threatening.
A man has been held on suspicion of attempted murder.
Officers said counter terrorism police were leading the inquiry, but they were keeping an open mind on the motive.