A man from Greater Manchester has been accused of posting comments supporting the terrorist attack in New Zealand.
The 24-year-old from Oldham was arrested on Saturday afternoon on suspicion of sending malicious communications, police said.
There were no details given about what he is alleged to have written.
The arrest comes after 49 people were killed at two mosques in the New Zealand city of Christchurch by a terrorist thought to have been a white nationalist.
A GMP spokesman said: “This is a very difficult time for people. The events in New Zealand have reverberated around the world. Many people are in deep shock and are worried.
“It is at times like this that, as a community, we stand together.
“Where the law permits and people cross the line, we will take robust action, which may include arrest and prosecution.”
Brenton Tarrant, an Australian 28-year-old, has appeared in court charged with murder in connection with the mosque attacks.
He was remanded to reappear on 5 April.