The UN agency which provides assistance and protection for Palestinian refugees is temporarily closing all its relief and distribution centers in the Gaza Strip, after demonstrators stormed its office there, a UN spokesperson said on Friday.

On Thursday, demonstrators stormed the compound of the Gaza Field Office of the UN Relief and Works Agency for Palestinian Refugees (UNRWA), in response to a program cut necessitated by budget shortfalls, said deputy UN spokesman Eduardo del Buey at a daily news briefing here.

"The incident is a dramatic and disturbing escalation in a series of demonstrations that have taken place over the past week, " UNRWA said in a statement.

"These demonstrations affect our ability to provide much-needed service to the Palestine refugees in Gaza and -- because they also targeted the Gaza headquarters building -- our operations in the West Bank, Jordan, Lebanon and Syria," the statement said.

The agency's Gaza director, Robert Turner, stressed that UNRWA respects people's right to peaceful demonstration, but added that what happened was "completely unacceptable" and could have resulted in serious injuries to staff and demonstrators, according to del Buey.

Many of UNRWA's other facilities had already been shut down due to the demonstrations. With this additional protest, UNRWA said that the safety of its staff is of crucial concern, and that it would close all its relief and distribution centers "until guarantees are given by all relevant groups that UN operations can continue unhindered."

UNRWA announced earlier that it would reduce its cash assistance program due to a 35-million-US-dollar budget shortfall.

The agency has called on all the groups behind the incident "to immediately stop inciting crowds at these demonstrations and to conduct themselves in a responsible manner."

It also called on authorities to play their role in providing security and ensuring demonstrations remain peaceful, and encouraged donors to continue to fund vital UNRWA relief programs.