Palestinian President Mahmoud Abbas has told the British Broadcasting Corp. he has "credible evidence" a BBC journalist kidnapped a month ago in the Gaza Strip was "safe and well," the BBC's top executive said Thursday.

Alan Johnston, a native of Scotland, was abducted at gunpoint in Gaza City on March 12. There has been no sign of life from him since, and no word from his captors.

No other foreigner has been held in Gaza as long.

BBC director general Mark Thompson appealed for Johnston's release at a news conference in the West Bank town of Ramallah. At a meeting with Abbas on Wednesday, "he told me that he had credible evidence that Alan was safe and well," Thompson said.

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Thompson said there have been no contacts with Johnston's captors, and no demands from them.

"It is vital for all journalists to be able to report freely and without fear of harrassment and intimidation," he told the news conference.

"I appeal to all those who may have influence with the kidnappers to use their best endeavors to secure Alan's release, safely and speedily, and to ensure his return to his family and friends as quickly as possible," he said.

Thompson said he did not know why the case was taking so long to be resolved. More than a dozen foreign journalists and aid workers have been abducted by Gaza gunmen in the past 18 months, often in a bid to wrest money or jobs. Most have been released unharmed within hours or days.

The one exception was the abduction of two FOX News employees in August, which lasted two weeks before they were freed, unharmed.

Thompson's appeal for Johnston's release was part of a daylong calendar of international events meant to dramatize the abducted journalist's plight, including a statement from his parents. A rally was held in Gaza simultaneously with the news conference in Ramallah.