The US government has urged Israel to substantially increase humanitarian aid for people in the Gaza Strip, as Israel terminates cooperation with a UN relief agency.

Israel said on Monday that it has notified the United Nations that it has decided to end cooperation with the UN agency for Palestinian refugees, known as UNRWA.

Observers fear the humanitarian situation in Gaza could worsen further, since UNRWA plays a major role in distributing humanitarian aid and providing medical care in Gaza. Cooperation with Israel is essential for the UN agency to operate in Gaza.

Also on Monday, US Secretary of State Antony Blinken spoke with Israel's Defense Minister Yoav Gallant over the phone.

The US State Department says Blinken urged Israel to take further actions to substantially increase humanitarian aid, including food and medicine, to civilians across Gaza.

Israeli forces are continuing with military offensives against the Palestinian Islamic group Hamas in Gaza and the Lebanese Shia Muslim group, Hezbollah.

The Israeli military said on Tuesday that their troops eliminated dozens of Hamas fighters in Jabalia in northern Gaza.

A Palestinian media outlet reported on the day that four Palestinian civilians were killed in Israeli airstrikes in Gaza City in the northern enclave.

The Israeli military on Monday also announced they conducted an air strike on targets belonging to Hezbollah's intelligence headquarters in Syria.

Syria's defense ministry said Israel targeted civilian sites south of the capital Damascus and caused some damage.