(CNN) The two teenagers who had been arrested in connection with the killing of investigative journalist Lyra McKee were released without charges on Sunday, police in Northern Ireland said.

The two men, aged 18 and 19, had previously been arrested under the terrorism act, the Police Service of Northern Ireland tweeted.

McKee, a 29-year-old prominent freelance journalist who wrote for publications including The Atlantic and Buzzfeed News, was killed in the Creggan area of Londonderry, also known as Derry, on Thursday night in what police described as a terrorist incident.

The release of the two men comes the same day that Sinn Féin Vice President Michelle O'Neill called on those who brought guns to the streets of Derry to disband and end their actions.

"The people who brought guns onto the street, and those who organize them do not represent any version of Irish republicanism," O'Neill said at the Easter Commemoration in Derry.

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