A BBC spokesman said: "Clearly we welcome this news, but what Alan's family and the BBC want more than anything else is firm evidence of Alan's well-being and his immediate release."

Meanwhile, Graham Johnston, the journalist's father, called it "really good news," saying: "This is the news I've been waiting to hear and I don't think the Palestinian president would say this unless he was convinced it was true.

"But we still don't have proof of life. That's what I want desperately. It's been nearly six weeks now."

Barghouti plea

A senior leader of the second Palestinian uprising also called on Thursday for the release of Johnston, describing him as "a friend of the Palestinian people".

Marwan Barghouti, the West Bank leader of Fatah, made the appeal from the Israeli prison where has been held for nearly three years.

"From my prison cell and in the name of the 10,000 Palestinian prisoners I call for the immediate release of journalist Alan Johnston, a friend of the Palestinian people," he said.

He rejected "kidnappings and aggressions that enormously harm Palestinian interests and our national struggle".

Abducted

Johnston, 44, was seized at gunpoint as he drove home from work in Gaza City on March 12.

One of the few western reporters to have both lived and worked in Gaza, he has become the longest-held kidnapped westerner in the territory.

On Sunday, an Islamist group called the Kataeb al-Jihad al-Tawheed (The Brigades of Holy War and Unity) claimed in a statement to have killed Johnston.

However, Palestinian authorities say there is no proof that the claim by the little-known group was true.