UNITED NATIONS - UN Secretary-General Antonio Guterres is alarmed by the resumption of hostilities between Israel and Palestinians after a short pause, said his spokesman on Monday.

The secretary-general is extremely alarmed by the resumption of hostilities between Israel and Hamas and other armed Palestinian groups in Gaza over the weekend, including rocket fire toward Israel from Gaza and the renewal of ground operations and intensified airstrikes by the Israel Defence Forces in southern Gaza, said Stephane Dujarric, the spokesman, in a statement.

Guterres calls on all parties to respect their obligations under international humanitarian law. The United Nations continues to appeal to Israeli forces to avoid further action that would exacerbate the already catastrophic humanitarian situation in Gaza and to spare civilians from more suffering. Civilians, including health workers, journalists and UN personnel, and civilian infrastructure must be protected at all times, said the statement.

"The secretary-general reiterates the need for unimpeded and sustained humanitarian aid flow to meet the needs of the people throughout the (Gaza) Strip. For people ordered to evacuate, there is nowhere safe to go and very little to survive on," it said.

Guterres also remains gravely concerned about the escalation of violence in the occupied West Bank, including intensified Israeli security operations, high numbers of fatalities and arrests, spiking settler violence and attacks on Israelis by Palestinians, it said.

The secretary-general reiterates his call for a sustained humanitarian cease-fire in Gaza and the unconditional and immediate release of all remaining hostages, said the statement.