AVA- The group did not say in its March 17 statement why it targeted Sultan Mahmoud Khirkhwa, a 60-year-old reporter who was shot in the head by gunmen in the provincial capital of Khost.
Khirkhwa worked for the private television station Zhman. The men who attacked him were reportedly shot dead.
He was the fourth journalist to be killed in Afghanistan this year.
The killing follows that of Afghan TV journalist Nisar Ahmad Ahmadi, who was killed in a car bomb blast in the southern province of Helmand last week.
A regional group, the Journalists' Safety Committee, issued an appeal on March 16 calling for the government to do more to protect journalists in Afghanistan.
Afghanistan was the deadliest country for journalists worldwide last year, with at least 13 of them killed in relation to their work, according to the New York- based Committee to Protect Journalists.