Airstrike on Syria jail kills 39

At least 39, but up to 51 people are believed to have been killed in an airstrike on a Syrian jail.

A young Syrian walks amid the debris of airstrikes carried out by forces allied with the al-Assad regime. Source: AAP

Activists are reporting that an airstrike on a prison run by al-Qaeda's affiliate in Syria has killed at least 39 people.

The Britain-based Syrian Observatory for Human Rights said 39 people were killed, including many fighters from the Nusra Front as well as detainees in the northwestern town of Maaret al-Numan.

The Local Co-ordination Committees, another activist group, said the airstrike killed 51.

Conflicting figures are common in the aftermath of airstrikes in Syria.

The Observatory said warplanes fired four missiles that hit the Islamic court that includes a jail as well as a nearby road linking the court with a market.