October 7 Timeline: How Hamas Attack on Israel Triggered the Gaza War in 2023

The Oct. 7, 2023, Hamas-led attack on Israel became the starting point of a war that rapidly transformed Gaza, with Israel launching heavy bombardment of the densely populated enclave within hours and Palestinians facing mass displacement, destruction, and a deepening humanitarian crisis.

The conflict began after Hamas and other Palestinian armed groups launched thousands of rockets from Gaza and breached the perimeter fence separating the enclave from Israel on Oct. 7.

Armed fighters entered Israeli communities and military facilities, killing civilians and soldiers and taking hostages into Gaza. The United Nations has described the attacks as involving deliberate attacks on civilians and the taking of hostages.

But the events of Oct. 7 quickly developed into a far wider war. Israel declared war on Oct. 8 and began an intensive air campaign against Gaza.

Within the first several days, UN officials reported that hundreds of Palestinians had been killed, thousands injured, and at least 200,000 people displaced from their homes. Homes, schools, medical facilities, and other civilian infrastructure were damaged or destroyed.

Oct. 7: The Attack That Changed the Conflict

The assault began early on Oct. 7, when Palestinian armed groups fired rockets toward Israel and fighters crossed into southern Israel. Israeli communities and military positions near Gaza were attacked, while civilians and soldiers were killed or captured.

The scale of the assault shocked Israel and prompted the government to declare a state of war. The United Nations later said more than 1,200 people were killed and 251 people were abducted and taken to Gaza.

For Palestinians, however, the day also marked the beginning of a devastating new phase of warfare in Gaza. Israeli strikes began the same day, and the intensity of the bombardment increased rapidly.

Oct. 8: Israel Declares War, and Gaza Is Bombarded

On Oct. 8, Israel formally declared war and expanded its air campaign against Gaza. The territory, home to more than two million people, was already densely populated and subject to a long-standing blockade.

UN humanitarian officials warned within days that the consequences were becoming catastrophic. Thousands of Palestinians had been killed or injured, while hundreds of thousands were being forced from their homes.

The destruction was not limited to military sites. Residential buildings and essential infrastructure were also hit, raising questions about whether Israel’s military operations were complying with international humanitarian law.

Mass Displacement Spreads in Gaza

As Israeli bombardment continued, Israel ordered residents of northern Gaza to move south. Hundreds of thousands of Palestinians fled their homes, often carrying only essential belongings and seeking shelter in increasingly crowded areas.

Humanitarian conditions deteriorated as Gaza faced shortages of food, water, fuel, and medical supplies. Aid deliveries were initially limited, with the first trucks entering through the Rafah crossing on Oct. 21 after days of diplomatic negotiations.

The bombing’s consequences became increasingly visible. A UN report later found that by Oct. 31, approximately 45% of Gaza’s housing units had been destroyed or damaged.

It also raised serious concerns about Israel’s compliance with the principles of distinction, proportionality, and precaution under international humanitarian law.

November: A Brief Pause

After weeks of fighting, Israel and Hamas reached a temporary truce in November. The pause allowed some hostages held in Gaza and Palestinian prisoners held by Israel to be exchanged, while additional humanitarian aid entered Gaza.

The truce did not end the conflict. Fighting resumed after the agreement expired, and Israeli military operations expanded further into Gaza.

Why October 7 Remains a Turning Point

Oct. 7 is remembered in Israel as the day of the country’s deadliest attack in decades. For Palestinians, it also marks the beginning of a war that brought unprecedented destruction to Gaza and displaced much of its population.

International investigators have since raised serious concerns about both sides’ conduct. A UN human rights report said Israeli attacks examined during the opening months of the war raised concerns about violations of international humanitarian law, while also noting that indiscriminate rocket fire by Palestinian armed groups raised similar concerns.

Three years later, Oct. 7 remains central to understanding the Gaza war. The Hamas-led attack triggered Israel’s declaration of war, but the military campaign that followed fundamentally reshaped life in Gaza, leaving Palestinians to confront widespread destruction, displacement and a humanitarian crisis whose consequences extended far beyond the first days of fighting.