Israel's Prime Minister Benjamin Netanyahu said his country's war against the Islamic group Hamas has entered its "second stage," with more ground troops entering the Gaza Strip.

Israeli forces are expanding their military operations in the area, which is under Hamas' effective control.

Netanyahu also renewed his call for Gaza residents to evacuate to the south, indicating that Israeli forces will further intensify their offensive in the strip's northern part.

The Israeli military announced the expansion of its ground operation in Gaza on Sunday. It also said it bombarded at least 450 Hamas positions over the past two days.

Hamas released footage it claims to show its attack on Israeli military vehicles with anti-tank missiles in Gaza's northeast, suggesting that a fierce ground battle is underway.

The chief of staff of the Israeli forces echoed Netanyahu's remarks, saying that the war has multiple stages and has moved onto the next stage.

Analysts say such statements indicate that Israel plans to ratchet up its ground operations depending on the situation, rather than launching a full-scale ground offensive all at once.

A military spokesperson said time is running out for Gaza residents to head south, and added that more food, water and medicines will be brought into the southern part of the strip.

But Israel remains adamant that it will not allow gasoline and other fuels to be brought in.

The Palestinian Red Crescent Society released a voice message from Gaza on Sunday. It said three ambulances were unable to operate due to a shortage of fuel.

In the meantime, clashes between the Israeli military and the Lebanon-based Shia militant group Hezbollah are intensifying near the border between Lebanon and Israel.

On Saturday, anti-tank missiles and mortar were fired from the Lebanese side, while Israeli fighter jets bombed Hezbollah facilities.

Israel is wary of Hezbollah joining the war as the group has superior military capabilities to Hamas. Observers say Hezbollah's moves may affect an Israeli decision on whether to launch a full-scale ground incursion into Gaza.