The state-run Syrian Arab News Agency (Sana) reported widespread damage and heavy casualties around the Zeyzoun Dam, near the town of Hama, about 350 kilometres (220 miles) north of Damascus.

Cracks appeared... leading to a rush of water, then the collapse of the dam, causing massive damage to a number of villages and their residents

Syrian news agency

But government information officials later said they believed there were few people hurt or killed in the incident.

Telephone lines in the area are down and details of what has happened remain unclear.

BBC Middle East correspondent Paul Wood says Syria has been criticised in the past for minimising incidents that may reflect badly on the government.

Cracks were first noticed in the dam around midday local time (0900 GMT), state media reported.

Sudden torrent

As water began to flow through them and the cracks widened, surrounding villages began to be evacuated.

Then there was a sudden deluge of water through a six-metre-wide split and the dam collapsed at 1540.

Sana news agency's report said: "Cracks appeared in the Zeyzoun dam... leading to a rush of water, then the collapse of the dam, causing massive damage to a number of villages and their residents."

The Ministry of Irrigation has set up an emergency committee to co-ordinate rescue efforts and determine the causes of the collapse, Sana said.

Huge capacity

State television reported that Prime Minister Mohammad Mustapha Miro would be in overall control of the investigation.

The Zeyzoun Dam was built with a capacity of 71 million cubic metres in 1996 on the Orontes River which has been used for irrigation of the surrounding countryside for centuries.

Ancient wooden waterwheels on the river, known as norias, are a local tourist attraction.

The dam is in al-Ghab region, home to about 200,000 people, which mostly consisted of marshes until a series of dams was built.