The New IRA has admitted responsibility for the kiling of Northern Irish journalist Lyra McKee. The group had come under increasing pressure to own up to the crime, which police described as a "terrorist act."

The armed republican group known as the New IRA on Tuesday admitted to the killing of journalist Lyra McKee in the city of Londonderry/Derry last week.

The group made the admission in a statement to The Irish News newspaper.

McKee was shot dead during a riot as dissident republicans clashed with police last Thursday in the city's Creggan district.

"In the course of attacking the enemy, Lyra McKee was tragically killed while standing beside enemy forces," the statement said.

"The IRA offer our full and sincere apologies to the partner, family and friends of Lyra McKee for her death," it added.

The New IRA, which formed in 2012, accused police of provoking rioting that preceded the gun attack in which McKee died. The group rejects the Good Friday agreement of 1998, which brought to an end three decades of a sectarian conflict in Northern Ireland that claimed more than 3,600 lives.

The admission and apology came after far-left republican political group Saoradh, which is associated with the New IRA, called for the organization to apologize.

Saoradh canceled a dissident republican Easter march on Monday "as a mark of respect."

'Blood on their hands'

However, Saoradh has come under heavy criticism for its perceived role in stoking sectarian hatred. 

Friends of the journalist held a protest at Saoradh headquarters on Monday, using a pot of red paint to place handprints on the walls of the building.

"We have used red paint because they have blood on their hands for what has happened," said protester Sinead Quinn, a friend of McKee.