Israel's Prime Minister Benjamin Netanyahu announced an "emergency government" with an opposition party leader, Benny Gantz, for the duration of the war.

"Following a meeting ... held today, the two agreed on establishing an emergency government and war cabinet," said on Wednesday in a joint statement by the premier and Gantz, a former defence minister.

Opposition leader Yair Lapid has not joined Gantz, but the statement said a seat would be "reserved" for him in the war cabinet.

In a dramatic escalation of Mideast tensions, Israel declared war on Gaza, a response to a military operation by the Palestinian group Hamas in Israeli territories.

The conflict began when Hamas initiated Operation Al Aqsa Flood against Israel, a multi-pronged surprise operation including a barrage of rocket launches and infiltrations into Israel via land, sea, and air, which Hamas said was in retaliation for the storming of the Al Aqsa Mosque in occupied East Jerusalem and Israeli settlers’ growing violence against Palestinians.

In response to Hamas' actions, the Israeli military launched Operation Swords of Iron against Hamas targets within Gaza.

Israel's response has extended into cutting water and electricity supplies to Gaza, further worsening the living conditions in an area that has reeled under a crippling siege since 2007.