United Nations workers have launched a protest against an air strike that struck an aid convoy near the Syrian city of Aleppo.

The protesters on Wednesday called the attack a "horrible" act and an infringement of international humanitarian law.

The United Nations suspended aid convoys across Syria on Tuesday, one day after the attack killed at least one aid worker and around 20 civilians. A warehouse and a hospital were also destroyed.

The International Committee of the Red Cross has also postponed an aid convoy that had been set to deliver supplies to four besieged Syrian towns.