Suicide bomber kills 31 in Syria's Hama

The Syrian Observatory for Human Rights says at least 31 people have died in a suicide attack in the central city of Hama.

At least 31 people have died in a suicide attack in Syria's central city of Hama. (AAP)

A suicide bomber has blown up a truck packed with explosives at an army checkpoint in Syria's central city of Hama, killing at least 31 people.

"At least 31 people, including regime troops, were killed when a man detonated a truck laden with explosives at a checkpoint near an agricultural vehicles company on the road linking Hama to Salamiyeh," the Syrian Observatory for Human Rights said on Sunday.

The Britain-based watchdog said the death toll was likely to rise, as "there are dozens of wounded, some of them in critical condition".

State news agency SANA reported that the blast left 30 dead and injured dozens.

Quoting an unnamed official, SANA said "a terrorist bomber blew himself up in an explosives-laden truck at the eastern entrance to Hama city on the road to Salamiyeh, killing 30 people and injuring dozens of others".

The blast "hit an area with busy traffic, just as a truck carrying gas for home use was passing," said the agency.

The explosion damaged at least 20 vehicles and several homes and shops.

Pro-regime broadcaster Al-Ikhbariya aired footage from the scene of the blast, showing widespread damage.

It also broadcast images of torn body parts, and vehicles in flames.

In the first months after the uprising against President Bashar al-Assad's regime erupted in March 2011, Hama saw some of the largest demonstrations against his rule.

But in late summer of that year, security forces stormed the city, killing scores of people. They have held a tight grip on the city ever since.