Lev Radin/Sipa USA/AP/File
UN Secretary-General spokesperson Stephane Dujarric speaks at UN headquarters in New York on July 1.
CNN  — 

Shots were fired during the Israeli military’s hours-long detention of a convoy of United Nations vehicles in Gaza, the UN Secretary General’s spokesperson said Tuesday.

The situation “escalated quickly” after the Israel Defense Forces (IDF) stopped the convoy at a checkpoint on Monday and demanded to take two of its 12 passengers for questioning, according to the spokesperson, Stéphane Dujarric.

Dujarric said the Israeli soldiers had pointed their weapons at the UN personnel and that at some point during the incident “shots were fired.”

He said IDF tanks and bulldozers then “proceeded to ram the UN vehicles from the back and front, compacting the convoy with UN staff still inside.”

“One bulldozer dropped debris on the first vehicle, while Israeli soldiers threatened staff, making it impossible for them to safely exit their vehicles,” he added.

The convoy was later released and UN officials have confirmed their staff returned safely to a UN base.

CNN has asked the IDF for comment on Dujarric’s account of the incident, which took place at the Wadi Gaza checkpoint.

Previously, the IDF said it had acted “following intelligence that a number of Palestinian suspects were present in the convoy.”

The Israeli military had also claimed previously that the convoy was not involved in the transport of polio vaccines but was being used instead to exchange UN personnel.

However, the UN has insisted that the convoy was involved in polio vaccinations and contained national and international staff members who were meant to be rolling out the campaign for children in Gaza City and northern Gaza.

Dujarric said that despite the incident, vaccinations were able to begin in northern Gaza on Tuesday – the third phase of the UN-led campaign which is expected to continue through Thursday.

On Monday, Philippe Lazzarini, chief of the UNWRA – the UN’s main agency for Palestinian humanitarian relief – criticized the IDF’s conduct in the incident as “the latest in a series of violations against UN staff including shootings at convoys and arrests by the Israeli Armed Forces at checkpoints despite prior notification.”