According to local Palestinian authorities, the pair were in a United Nations vehicle displaying the UN flag and insignia when they were targeted.
Waibhav Anil Kale, 46, began working with the United Nations Department of Safety and Security in Gaza last month.
Farhan Haq, deputy spokesman for the UN secretary-general, confirmed that a staff member had been killed in Gaza.
“With the conflict in Gaza continuing to take a heavy toll – not only on civilians, but also on humanitarian workers – the secretary-general reiterates his urgent appeal for an immediate humanitarian ceasefire and for the release of all hostages,” he said.
The government in Gaza announced: “We strongly condemn the ongoing atrocities perpetrated by the Israeli occupation against both the Palestinian population and foreign aid workers in Gaza.”
“We urge all nations to denounce these reprehensible acts,” it added.
According to Israeli daily newspaper Haaretz, Israeli officials said they were aware of an incident in which one person was killed and another wounded.
The Israeli military claimed it was investigating the killings.
Since October, at least 216 aid workers have killed in Gaza, the vast majority of whom were Palestinians killed by Israeli aerial bombardment, according to figures compiled by the Aid Worker Security Database.
In April, Israeli drone strikes killed seven aid foreign workers from the World Central Kitchen (WCK) after they brought a new shipment of food into the famine-afflicted territory.
The attack on WCK workers highlighted the flawed humanitarian notification system in Gaza.
At least 357 humanitarian-run sites and convoys in Gaza whose coordinates had been shared in advance with warring parties were hit before the WCK attack, Middle East Eye previously reported.
The majority of the hits to deconfliction humanitarian sites – 352 – were to locations run by UNRWA, the largest aid organisation operating in Gaza, including a food distribution centre and schools sheltering thousands of civilians.
