A number of Irish journalists have been "formally notified" by police in the Republic of Ireland that their safety is at risk from organised criminals.
It follows two killings in a gangland feud in Dublin in the past week.
In a statement, Independent News and Media (INM), which owns the Irish Independent newspaper, said it was working with police to increase security around its reporters.
Editor-in-Chief Stephen Rae said they "would not be deterred".
He added: "This is an outrageous threat to the freedom of the press in Ireland and we are taking the threats with the utmost seriousness.
"Our media group will not be deterred from serving the public interest and highlighting the threat to society at large posed by such criminals."
Group managing editor of the INM, Edward McCann, said the "people in question" had been "formally notified" by Irish police that their safety was at risk from organised criminals.
"As journalists our duty is to report the facts and to expose stuff and sometimes that makes it uncomfortable for criminal elements and in this instance, obviously, there's a risk from organised criminals in relation to reporting of incidents," he said.
"Both An Garda Síochána and Independent News and Media are treating the threats very seriously and measures are being put in place. We're very conscious of the safety of all our staff."
Mr McCann said the paper was well aware of the dangers that journalists faced.
"INM has lost two journalists in the last 20 years," he said.
"Veronica Guerin and then there was Martin O'Hagan in Northern Ireland so we're well aware as a group of the dangers posed to journalists."
The National Union of Journalists (NUJ) Irish secretary, Seamus Dooley, said he was "gravely concerned at the development".
"Journalists and media organisations will not be intimidated by such threats, which have no place in a democratic society," he said."
"Our immediate thoughts are with those under threat and their families. No journalists should be placed under threat for doing their job."
On Tuesday, Irish police said they were working to set up a permanent armed support unit for Dublin in the wake of the gangland-style shootings.
BBC News NI reporter Lisa McAlister, who is in Dublin, said gardaí could not comment on individuals or the threats facing them, but said they do have processes in place and take all threats seriously.