Islamic State (IS) militants in Syria have entered the Unesco World Heritage site of Palmyra after seizing the town next to the ancient ruins, reports say.

Unesco says its destruction would be "an enormous loss to humanity", but no damage has been reported there yet.

IS now controls the nearby airport, prison and intelligence HQ, the Syrian Observatory for Human Rights says.

The militants have previously demolished ancient sites in Iraq that pre-date Islam.

The BBC's Jim Muir in Beirut says acute international concern over Palmyra might actually spur the jihadists on to make destroying the site a priority.

The remains, like the ancient theatre, drew throngs of tourists before the war
The remains, like the ancient theatre, drew throngs of tourists before the war

Talal Barazi, the Governor of Homs Province, which includes Palmyra, told the Associated Press that 1,300 people had fled the city over the past few days, and more were trying to leave.

... Unesco's director-general, Irina Bokova, said any destruction to Palmyra would be "not just a war crime but... an enormous loss to humanity".

"It belongs to the whole of humanity and I think everyone today should be worried about what is happening," she said in a video statement.

... Syria's head of antiquities, Maamoun Abdul Karim, said on Wednesday that hundreds of Palmyra's statues had been moved to safety but that large monuments could not be transferred.