The BBC says it's concerned about reports that its correspondent Alan Johnston has been killed a month after he was feared abducted in Gaza, but stresses nothing has been verified.

The British Broadcasting Corporation said on Sunday that it's aware of the reports and is "deeply concerned" about what it's hearing, but stressed "it is rumour with no independent verification."

British Broadcasting Corporation correspondent Alan Johnston is seen in this undated photo taken in the Gaza Strip.
(Mahmud Hams/AFP/Associated Press)

A Palestinian group calling itself the Al Tawhid Al Jihad brigade issued a claim that it killed Johnston, the reports said.

"The group is apparently little known in the Palestinian context," the BBC's Mike Wooldridge said.

It's believed Johnston, who is 44 and the only Western correspondent who lives in Gaza, was taken from his car as he drove home from work on March 12. He had worked in Gaza for three years.

Last Thursday, to mark a month since his disappearance, other leading news organizations joined the BBC in what was dubbed an international Day of Action to highlight his plight and renew calls for his release.

On the same day, Johnston's father, Graham, in a second broadcast appeal for his son to be released, said, "Please think about what this is doing to my family."

A spokeswoman for the Foreign and Commonwealth Office in London said it's aware of reports about an execution and is urgently looking into them.

The Palestinian Authority said it has no information confirming the fate of the journalist.

Arutz Sheva, an internet-based Israeli media network, reported that the Gaza group made its claim in a flyer and has ties to al-Qaeda.