Anadolu Agency via Getty Images A wounded man is seen after airstrikes near Aleppo, Syria on Tuesday.

BEIRUT (Reuters) - An air raid carried out overnight by Syrian or Russian warplanes killed four medical workers and at least nine rebel fighters near Aleppo, the Syrian Observatory for Human Rights monitoring group said on Wednesday.

The raid hit the town of Khan Touman southwest of Aleppo city, an area controlled by insurgents. The British-based Observatory said the rebels killed were from the Islamist alliance Jaish al-Fatah.

The medical staff killed were working for the Union of Medical Care and Relief Organizations (UOSSM), it said. UOSSM confirmed in a statement that four of its staff had been killed.