"What we're lacking is sanity and authority on the part of the leadership that are part of the UN Security Council," Luiz Inacio Lula da Silva said in an interview with Al Jazeera on Friday.
"If we had true leaders, if we had a body that makes a decision that would be respected and complied (with) — and that should be the body of UNSC (UN Security Council) — we would not have this war," he stressed.
Referring to the thousands of casualties, including children, and the bombing of hospitals in the Gaza Strip, Lula described the situation as "madness."
He emphasized that Israel has the right to self-defense but criticized the unnecessary killing of innocent women and children. He called for peaceful coexistence between the states of Palestine and Israel.
Urging a diplomatic solution to the conflict, Lula criticized US President Joe Biden for lacking the "sensitivity" to call for a halt to the fighting, pointing out Washington's influence over Israel.
Lula also criticized Israeli Prime Minister Benjamin Netanyahu, describing him as a leader with low sensitivity to humanitarian issues, emphasizing the need for respect towards the Palestinian people.
The Israeli army resumed bombing the Gaza Strip early Friday after declaring an end to a week-long humanitarian pause with the Palestinian resistance group, Hamas.
At least 178 Palestinians have been killed and 589 injured on Friday in Israeli airstrikes, according to the Gaza Health Ministry.
The humanitarian pause began on Nov. 24 as part of an agreement between Israel and Hamas to temporarily halt fighting to allow hostage swaps and aid delivery.
More than 15,000 Palestinians, mostly children and women, have been killed in Israeli attacks since Oct. 7 following a cross-border attack by Hamas.