LONDON, May 9 — Four men were arrested under terrorism laws today in connection with the killing of journalist Lyra McKee in Londonderry last month, Northern Ireland’s police force said.

"Detectives carried out searches at four houses in the city and arrested four people in connection with the violence which was orchestrated on the streets of Creggan on the evening of Lyra McKee’s murder,” said Police Service of Northern Ireland senior detective Jason Murphy.

The men, aged 15, 18, 38 and 51, are currently being questioned in custody under terrorism legislation, police added.

McKee, 29, who chronicled the troubled history of Northern Ireland, was shot in the head on April 18 as rioters clashed with police in the second biggest city in the British province.

Dissident republican faction the New IRA claimed responsibility on and apologised, saying the shots had been aimed at the police.

The killing evoked memories of the three decades of violence in the province and sparked condemnation across the political spectrum, including in the neighbouring Republic of Ireland.

McKee established her career writing about so-called "ceasefire babies” — the generation which came of age after the 1998 Good Friday Agreement which ended the conflict known as "The Troubles”.

Three people — two men aged 18 and 19 and then a 57-year-old woman — so far arrested by Northern Irish police in connection with McKee’s killing were all released without charge.

Her death follows a spate of letter bombings and a car bombing, also claimed by the New IRA.

It has fuelled fears that the political turbulence over Brexit — which threatens new border checkpoints on the Irish border — may increase paramilitary activity. — AFP