British counter-terrorism police have arrested a man on suspicion of sending letters entitled “Punish a Muslim Day” which provoked people around the country to commit violent acts. The man, whose name was not released to public, was arrested on Tuesday on suspicion of sending letters conveying a threatening message and of sending a hoax noxious substance, Reuters reported. The 35-year-old from Lincoln in northeast England was later taken to a police station for questioning. “These letters seek to cause fear and offence among our Muslim communities. They also seek to divide us,” said Martin Snowden, head of Counter Terrorism Policing North East, in an earlier statement on the investigation. “Yet in spite of this our communities have shown strength in their response to such hatred and in their support for each other,” he added. According to Reuters, media reports about the letters caused widespread outrage, with tens of thousands of people taking to social media to show support for Muslims with hashtags such as #LoveAMuslimDay and #WeStandTogether. The letters, which designated April 3 as “Punish a Muslim Day” and proposed ranking acts of violence according to a points system, started arriving in some people’s post in March. Also among others, four members of parliament with South Asian backgrounds received copies.