JERUSALEM — Israel’s military said Wednesday it seized control of a strategic corridor along Gaza's border with Egypt to cut off smuggling tunnels as it tries to destroy the militant Hamas group in a war that is now in its eighth month.

The capture of the Philadelphi Corridor could complicate Israel’s relations with Egypt, which has complained about Israel's advance toward its border. Israel says the corridor is awash in tunnels that have funneled weapons and other goods for Hamas — despite a yearslong blockade imposed by Israel and Egypt.

Israel also deepened its incursion into the southern Gaza city of Rafah, where hundreds of thousands have been seeking shelter from fighting, and where intensifying violence in recent days has killed dozens of Palestinians. The military said that a fifth brigade — up to several thousand soldiers — joined troops operating in the city on Tuesday.

Egypt says any increase in troops in the strategic border area would violate the countries’ 1979 peace accord. It already has complained about Israel taking over the Rafah border crossing, the only crossing between Gaza and Egypt.

“The Philadelphi Corridor served as the oxygen line of Hamas through which Hamas carried out weapons smuggling into Gaza on a regular basis,” said Israel’s military chief spokesperson, Rear Adm. Daniel Hagari.

An Israeli military official said Israel had notified Egypt of the takeover. Some 20 tunnels, including some previously unknown to Israel, were found, as well as 82 access points to the tunnels, said the official, speaking on condition of anonymity in line with military regulations. It was not clear if the tunnels were currently in use.

The corridor is part of a larger demilitarized zone along the entire Israel-Egypt border. Under the peace accord, each side is allowed to deploy only a small number of troops or border guards in the zone, though those numbers can be modified by mutual agreement. At the time of the accord, Israeli troops controlled Gaza, until Israel withdrew its forces and settlers in 2005.

Egypt's state-run Al-Qahera News TV reported there were “no communications with the Israeli side” on the allegations of finding tunnels on the border. Egypt has repeatedly expressed concerns that the Israeli offensive could push Palestinians across the border — a scenario Egypt says is unacceptable.

The narrow corridor — about 100 yards wide in parts — runs the 8.6-mile length of the Gaza side of the border with Egypt and includes the Rafah crossing into Egypt.

Hamas has had free rein of the border since its 2007 takeover of Gaza.

Smuggling tunnels were dug under the Gaza-Egypt border to get around the Israeli-Egyptian blockade, imposed after Hamas took over. Some of the tunnels were large enough for vehicles. Hamas brought in weapons and supplies, and Gaza residents smuggled in commercial goods, from livestock to construction materials.

That changed over the past decade, as Egypt battled Islamic militants in Sinai. The Egyptian military cracked down on the tunnels and destroyed hundreds of them.

The Israeli military official said Israel has also taken “tactical control” of Tel al-Sultan, a neighborhood on Rafah's northwest edge. But he said the incursion into the city remains a “limited scope and scale operation.”

White House national security spokesman John Kirby said seizure of the Philadelphi Corridor would be consistent with the “limited” ground operation Israeli officials briefed President Joe Biden's team on for the city of Rafah.

“When they briefed us on their plans for Rafah it did include moving along that corridor and out of the city proper to put pressure on Hamas in the city,” Kirby told reporters Wednesday.

Meanwhile, deadly violence continued. The Gaza Health Ministry said an apparent Israeli strike killed two ambulance crew members on their way to evacuate casualties in Tel al-Sultan.

Earlier Wednesday, a top Israeli official said the war was likely to last through the end of the year — a grim prediction for a conflict that has killed tens of thousands, deepened Israel's global isolation and brought the region to the brink of a wider conflagration.

Israel's national security adviser, Tzachi Hanegbi, told Kan public radio he was “expecting another seven months of fighting” to destroy the military and governing capabilities of Hamas and the smaller Islamic Jihad militant group.

The army has said from the start the “war will be long,” he said. “They have designated 2024 as a year of war.”

Hanegbi's remarks raise questions about the future of Gaza and what role Israel will play in it. The United States, Israel's top ally, has demanded that Prime Minister Benjamin Netanyahu decide on a postwar vision for the Palestinian territory. Netanyahu's defense minister and a top governing partner have warned he must take steps to ensure that Israel isn't bogged down in Gaza indefinitely.

The war has already devastated Gaza's urban landscape, displaced most of its population and sparked a humanitarian catastrophe and widespread hunger. It has opened Israel up to international legal scrutiny, with world courts faulting it over its wartime conduct, sparked disagreements with the White House, and on Tuesday prompted three European nations to formally recognize a Palestinian state.

Israel says it must dismantle Hamas' last remaining battalions in Rafah and will seek indefinite security control over the Gaza Strip, even after the war ends. Still, it has yet to achieve its main goals of dismantling Hamas and returning scores of hostages captured in Hamas' Oct. 7 attack that triggered the war.

Beyond Rafah, Israeli forces were still battling militants in parts of Gaza the military said it wrested control of months ago — potential signs of a low-level insurgency that could keep Israeli troops engaged in the territory.

The fighting in Rafah has displaced 1 million people, the United Nations says, most of whom were already displaced from other parts of Gaza.

Residents said fighting was underway in the city center and on the outskirts of Tel al-Sultan, the same neighborhood where an Israeli strike over the weekend ignited a fire that swept through an encampment for displaced people, killing dozens. Israel said it was investigating and the blaze may have been caused by a secondary explosion.

A floating pier built by the U.S. to surge aid into the territory was damaged in bad weather, another setback to efforts to bring food to starving Palestinians. Gaza's land crossings are now entirely controlled by Israel.

The U.S. and other allies have warned against a full-fledged offensive in Rafah, with the Biden administration saying this would cross a “red line” and refusing to provide offensive arms for such an undertaking. But so far, it hasn’t tried to stop Israel's advances.

Last week, the International Court of Justice ordered Israel to halt its Rafah offensive as part of South Africa’s case accusing Israel of committing genocide against the Palestinians in Gaza, a charge Israel denies.

The war began when militants burst into southern Israel on Oct. 7, killing some 1,200 people, most of them civilians, and taking around 250 hostages. More than 100 were released during a November cease-fire in exchange for Palestinians imprisoned by Israel.

Israel’s offensive in response to the attack has killed at least 36,096 Palestinians, according to Gaza’s Health Ministry, which does not distinguish between fighters and civilians. Israel says it has killed 15,000 militants.