The Israeli military intercepted a convoy of the United Nations in Gaza on Monday, claiming that a number of "Palestinian suspects" were in the vehicles.

The convoy had been stopped in order to question the suspects. The vehicles in question were transporting U.N. employees, the Israel Defense Forces (IDF) said.

"We emphasize that this is not a convoy carrying polio vaccines, but a convoy whose purpose is to exchange U.N. personnel. The incident is not yet over," an Israeli military spokesperson said.

Israeli television channel Kan reported that two suspected Palestinians had "infiltrated" the convoy and barricaded themselves in one of the vehicles. Israeli soldiers fired warning shots, the report said.

U.N. spokesman Stéphane Dujarric told dpa: "At this stage all I can say that we are aware of an ongoing incident involving UN personnel and vehicles. (We are) working to establish the facts (and our) number one priority is the safety and security of our colleagues."

Relations between Israel and the United Nations have been particularly strained during the ongoing war in Gaza.

Last month, the U.N. reported that Israeli soldiers fired on a U.N. humanitarian vehicle in a convoy, prompting the Israeli military to announce an investigation into the incident. Israel also targeted UNRWA schools, and refugee camps killing thousands of civilians.