Palestinian President Mahmoud Abbas said Thursday his intelligence services have confirmed that a British journalist kidnapped in Gaza is alive and he knows which group is holding him.

Alan Johnston, 44, a BBC correspondent, was abducted by gunmen on March 12 and has not been seen or heard from since then.

"Yes, I believe he is still alive," Abbas told reporters in Stockholm. "Our intelligence services have confirmed to me that he's alive."

Click here for more news from the Mideast.

Abbas said he knew which group was holding Johnston, but he would not say whether any contact had been established with the captors.

"What I'm telling you is based on my intelligence and our intelligence service gathering," the president said, adding that he received reports that Johnston was alive "in the last three days."

On Sunday, a previously unknown group, the Brigades of Tawheed and Jihad, said it had killed Johnston to support demands for the release of Palestinian prisoners held by Israel. There has been no confirmation of the claim.

"We know the group that holds him," Abbas said, but declined to elaborate. "The less we talk about it the more we provide safe release."

Abbas said he was "exerting every possible effort ... to ensure the safety of Mr. Johnson and to ensure his immediate release."