An extremist Taliban splinter group has claimed responsibility for killing a Swedish-British journalist in Kabul, the Associated Press reports.

Nils Horner had worked for Swedish Radio since 2001 as a foreign correspondent. The 51-year-old was killed by a shot in the head as he was reporting on Afghanistan's election on a street in Kabul on Tuesday, March 11.

It was a rare assassination of a foreigner in the capital and raised fears of increased violence ahead of the April 5 presidential election.

The Feday-e-Mahaz said in a statement posted Wednesday on its website that it targeted Horner because he was a spy for Britain's MI-6 agency, not a journalist.

The group was created by loyalists of slain Taliban commander Mullah Dadullah. The group broke with the Taliban following the announcement of talks with the United States.