Two men arrested in connection with the fatal shooting of Northern Irish journalist Lyra McKee were released without charge on Sunday, the Police Service of Northern Ireland said.

McKee, 29, was killed late Thursday while she was standing near police officers during rioting in the city of Londonderry. Officers apprehended the pair, ages 18 and 19, two days later under an anti-terrorism law.

Police suspect one or more gunmen linked to the New Irish Republican Army (New IRA) had fired on officers and had not intended to hit McKee.

The paramilitary group wants to unite Northern Ireland with the Republic of Ireland and rejects the 1998 Good Friday Agreement. The accord ended three decades of sectarian violence known as "The Troubles" that claimed some 3,600 lives.

Read more: Northern Ireland: Politicians condemn violence after journalist Lyra McKee's death

McKee's murder prompted condemnation from Irish and British politicians and renewed concerns about the fragile peace in Northern Ireland.

Detective Superintendent Jason Murphy called on anyone who recorded footage of the riots in Londonderry, which is known as Derry to Irish nationalists, to give police access to the recordings.

"We have received very positive support from the community, but we need to convert this support into tangible evidence that will enable us to bring Lyra's killers to justice," he said.

McKee's funeral is scheduled to be held on Wednesday in the capital, Belfast.

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