The family of a British aid worker thought to be being held by Islamic militants in Syria have urged his captors to contact them.
Islamic State (IS) extremists have threatened to kill David Haines and have not responded to any of the family's attempts to make contact so far, the Foreign and Commonwealth Office (FCO) said.
A statement on behalf of the family released by the FCO said: "We are the family of David Haines.
"We have sent messages to you to which we have not received a reply. We are asking those holding David to make contact with us."
Mr Haines was taken while working for ACTED in Syria in March 2013, having previously helped local people in Libya and South Sudan.
Militants from IS have beheaded two American journalists, posting the evidence online in gruesome videos featuring a masked jihadist with a British accent.
Foreign Secretary Philip Hammond has said the FCO will be doing "everything" they could to protect Mr Haines.
The 44-year-old has a teenage daughter in Scotland from a previous marriage and a four-year-old daughter in Croatia from his present marriage.
Educated at Perth Academy secondary school, he has worked for aid agencies in some of the world's worst trouble spots, including Libya and South Sudan.
He was in Libya during its civil war in 2011, working as head of mission for Handicap International, which helps disabled people in poverty and conflict zones around the world.
