The Israel Defense Forces (IDF) will invest $1.2bn in its Gaza Strip infrastructure over the next four years, a senior Israeli military official said on Tuesday.

The announcement came days after Israel’s Supreme Court ruled that a $1bn aid package to Egypt for rebuilding Gaza was unconstitutional because it didn’t take into account the deteriorating condition of the Gaza Strip.

In a statement, the IDF said it was “deeply concerned” by the ruling.

“The IDF will continue to work on enhancing the Gaza infrastructure, which is critical for its own security,” the statement said.

“We will be spending this money for the benefit of the people of Gaza and its citizens, not the profit of the international financial institutions that have taken the lead in the funding of Israel’s security establishment.”

The IDF added that it will work with the Palestinian Authority, the West Bank government and other partners to develop the infrastructure, including the power and water infrastructure.

The announcement comes as the West bank, which has been besieged by the Palestinian leadership, announced a massive military offensive to retake the Gaza strip from the Islamic State group (ISIS) group, which controls much of the territory.

The operation, to be launched by Israel on Wednesday, will be the largest military operation in Gaza since Israel’s offensive in 2014.

Last month, the Israeli military said it had retaken a third of the area, after Israeli airstrikes on militants in the area.

Israel’s Defense Minister Avigdor Liberman said on Wednesday that the offensive was designed to reclaim territory lost to the militants during Operation Protective Edge in 2014, when Hamas militants attacked the southern enclave.

The military said that Hamas militants had launched “large-scale attacks” against Israel on Tuesday in the Gaza city of Khan Yunis, as well as in other parts of the Strip, including in Beit Hanoun, and that it had “killed several members of the terrorist organization”.

In his speech, Liberman called on the international community to “use all our means” to stop the violence and urged Israel to be “the last resort”.

The UN has said more than 2,200 Palestinians have been killed in the six-week Israeli offensive, which began on July 8 and has left more than 1,100 Palestinians dead.

Israel launched the operation following rocket fire from Gaza on Israel in the West.