The Israeli military denied on Saturday that its forces fired on a United Nations convoy days earlier, dpa reported.
"We are 100 per cent certain we did not fire upon the truck," a spokesman for the Israeli military said.
Israeli military sources went further, saying they were fairly certain Hamas had been the source of the fire.
In the incident Thursday, the UN said two of its local employees were killed trying to bring humanitarian supplies from the northern Erez border crossing into the enclave.
UN Secretary General Ban Ki-moon, hours after the incident, issued a statement condemning Israel for the attack.
UN Relief Works Agency (UNRWA) spokesman Chris Gunness said the confusion regarding the incident warranted a deeper investigation that would "let the facts speak for themselves."
Following the incident, the UNRWA suspended all staff movement in the enclave, demanding security assurances from the Israeli military.
The UN said late Friday that it had received those assurances and it would resume full operations "as soon as possible."