Syrian aid convoy was tracked from the skies before attacks

Damaged aid trucks are pictured after an airstrike on the rebel held Urm al-Kubra town, western Aleppo city, Syria September 20, 2016. REUTERS/Ammar Abdullah

BEIRUT (Reuters) - Surveillance aircraft circled in the sky during the hours before a United Nations aid convoy was struck by warplanes on Monday, killing relief workers and destroying 18 trucks of humanitarian supplies, several witnesses said.

Rebels and local rescue workers say the surveillance shows the strikes, which have drawn outrage from the United Nations and Western countries, were deliberate, and gives the lie to Russian and Syrian government denials that they were involved.