A reporter covering the ongoing riots in Northern Ireland has been sent a bullet through the post in what is being seen as an intimidation tactic.

The Belfast-based journalist, who works for a news outlet in the city, was advised by the Police Service Northern Ireland that an envelope containing a bullet, addressed to the reporter personally, had been intercepted.

The letter had apparently been sent following the unnamed reporter’s coverage of loyalist rioting.

National Union of Journalists president Barry McCall has labelled the move a “despicable” attempt to intimidate journalists already working in a difficult environment.

“The posting of a bullet to a newspaper, addressed to a named journalist, represents an attack on journalism and on democracy,” he said.

“This incident must be seen in the context of recent attacks on journalists and elected public representatives and should be condemned by all who support the democratic process.”

The reporter is among a number of politicians who have been subject to similar postal threats, including nationalist Northern Ireland assembly member Patsy McGlone, who was sent a bullet and a sympathy card. The package was also intercepted by police.

NUJ general secretary Michelle Stanistreet said the incident emphasised the need for vigilance on the part of journalists and media organisations in Northern Ireland.

She added: “Employers and journalists – both staff and freelance – need to be alert to the very real dangers which arise when covering conflict situations.

“The lack of respect for the rights of journalists to work unimpeded present a particular challenge.

“The bullet sent in the post was clearly indeed to send a signal to the media. Over many years journalists have stood firm in the face of intimidation and they continue to do so.”

The rioting began as part of a protest by Loyalists over a decision by Belfast City Council not to fly the Union flag at Belfast City Hall 365 days a year.

Instead, the flag will only be flown on a handful of designated days, such as the Queen’s birthday.