Three aid workers were killed on Wednesday by an air strike near the Syrian city of Aleppo. (Representational Image)
The United Nations said it had received reports that three aid workers were killed on Wednesday by an air strike near the Syrian city of Aleppo.
The three relief workers were not employed by the United Nations.
"The UN deeply regrets this incident and remind once again all parties of their obligations under international humanitarian law to protect civilians and humanitarian workers," said UN spokesman Farhan Haq.
The spokesman did not specify whether the air strike was from Russian planes, which Syrian monitoring groups said have been heavily bombarding Aleppo over the past two days.
Syrian troops backed by Russian warplanes on Wednesday cut the last supply route linking rebels in Aleppo city to the Turkish border, a military source said.
Aleppo has been divided between loyalists in the west and rebels in the east since fighting erupted in the northern city in mid-2012.