A little-known Palestinian group has claimed to have executed Alan Johnston, the BBC's Gaza correspondent who was taken prisoner last month.
The BBC stressed Sunday there has been no independent verification of the claim by the group, "The Brigades of Tawheed and Jihad".
The group's message to news organizations said it killed Johnston because of Israel's refusal to release Palestinian prisoners.
When Johnston was abducted in Gaza City on March 12, he was the only Western reporter permanently based in the territory.
More than a dozen journalists and aid workers have been kidnapped in Gaza in recent months. Most have been released within hours or days.
On Thursday, the BBC's director general, Mark Thompson, said he had been told by Palestinian President Mahmoud Abbas that there was credible evidence Johnston was safe and well.
Some information for this report was provided by AP.