The BBC says it is concerned for the safety of a correspondent who has gone missing in the Gaza Strip.
The corporation said it had been unable to contact Alan Johnston, but did not comment on Palestinian reports that he had been kidnapped.
Johnston‘s car was found abandoned in Gaza City shortly after he left his office to drive home.
Several journalists and aid workers have recently been kidnapped in Gaza. All have been released unharmed.
Johnston, 44, has been the BBC‘s correspondent in the Gaza Strip for the past three years - and the only foreign journalist from a major media organisation based in Gaza.
‘We are currently unable to contact him and are concerned for his safety,‘ the BBC said in a statement.
‘We are trying to gather as much information as possible.‘
Details of what happened are sketchy. Palestinian police said four gunmen were seen in the vicinity of where Johnston‘s car was found.
Kidnapping rife
Most news organisations have pulled their staff out of Gaza in recent years, as violence between rival factions has spiralled and crime and lawlessness has increased.
A Peruvian photographer was kidnapped in January and held for a week, while in October a photographer for the Associated Press was held for 15 hours.
A team from Fox News were abducted last summer and filmed by their kidnappers during a two-week ordeal.
The Foreign Press Association, which represents foreign journalists in Israel and the Palestinian areas, issued an appeal, saying: ‘We ask all in Gaza to respect the rights and safety of the press.‘
Both the main Palestinian factions called for Johnston‘s release.
Palestinian Interior Minister Sayeed Sayyam, of the Hamas organisation, called his apparent abduction a ‘criminal act‘.
Fatah, the party of Palestinian President Mahmoud Abbas, declared a state of emergency and set up checkpoints to search for the reporter.
Three-year posting
The BBC described Johnston as a ‘highly experienced and respected reporter‘.
‘It is his job to bring us day after day reports of the Palestinian predicament in the Gaza Strip,‘ said the BBC‘s diplomatic correspondent, Paul Adams, himself a former Middle East reporter.
Alan Johnston was born in Tanzania and educated in Scotland. He joined the BBC World Service in 1991 and has spent eight of the last 16 years as a correspondent, including periods in Uzbekistan and Afghanistan.
He became Gaza correspondent in April 2004 and his posting was due to come to an end at the end of next month.