“The preparation for these convoys has now resumed and we are ready to deliver aid to besieged and hard-to-reach areas as soon as possible,” the UN’s humanitarian office (OCHA) said in a statement.
The Monday attacks came as relief supplies intended for desperate Syrian civilians were being unloaded at the warehouse Orum al-Kubra, a town in Aleppo province.
Those killed included volunteers as well as a Syrian Arab Red Crescent (SARC) staffer.
The UN announced it was suspending all deliveries on Tuesday morning and called for an investigation.
The Syrian Observatory for Human Rights, a monitor group, said the attack was the result of air strikes, which if confirmed, would strongly implicate Russian or Syrian aircraft as neither opposition nor jihadist groups have air power.
An unnamed US official told AFP that Washington believed a Russian plane was responsible.
Both Moscow and Damascus have denied involvement.
Boosting aid deliveries has become a top UN priority in Syria, with convoys repeatedly blocked for security reasons, refusals by the Syrian government to grant authorisation and strict conditions imposed by opposition groups.
OCHA on Wednesday restated its call for “safe, unconditional, unimpeded and sustained access to all Syrians in need, wherever they are.”