UN Secretary-General Antonio Guterres wrote to Israeli Prime Minister Benjamin Netanyahu on Tuesday to protest Israel's ban on the UN Relief and Works Agency for Palestine Refugees (UNRWA), which is essential for providing aid in Gaza, his spokesman said, according to Agence France-Presse.

"The law as we understand it gives 90 days before it comes into effect. We are in contact with the Israeli authorities," said Stephane Dujarric.

The spokesman continued: "The Secretary-General (...) sent a letter hours ago to the Israeli Prime Minister to emphasize his concerns and the issues that the law raises with regard to international law." Guterres also expressed his hope that the law, which was passed by the Israeli parliament on Monday, "will not be implemented."

For his part, an official at the United Nations Relief and Works Agency for Palestine Refugees (UNRWA) confirmed today that the UN organization is “indispensable” because its activities help keep the residents of the war-ravaged Gaza Strip “alive.”

On Monday, the Israeli parliament passed a law banning UNRWA from operating in Israel and occupied East Jerusalem, despite US objections. The bill was approved by a vote of 92 to 10.

UNRWA has been providing vital aid to the Palestinians for more than seven decades, and has denounced this “scandalous” measure against it.