Israel's military has taken control of the entire section of the Gaza Strip along the border with Egypt, army spokesman Daniel Hagari said late on Wednesday.
The Israel Defense Forces (IDF) had gained operational control of the area known as the Philadelphi Corridor, on the border between Egypt and Rafah, Hagari said.
The IDF had found about 20 tunnels used by the Palestinian militant group Hamas to smuggle weapons into Gaza there, Hagari said.
The information could not initially be independently verified.
Fighting has continued in southern Gaza despite continuing calls from world leaders for Israel to halt the operation immediately.
Three Israeli soldiers were killed when a booby trap exploded in a building in Rafah, Israeli media reported on Wednesday.
The Israeli army confirmed that three soldiers from the Nahal infantry brigade had been killed in fighting the previous day.
During the operation, Israeli soldiers went from house to house in search of weapons, the military said, without elaborating specifically on where or how they died. Local media said it was in a booby-trapped building in Rafah.
According to the army, the incident on Tuesday means that 639 Israeli service members have been killed and more than 3,600 others injured since the massacres by Hamas of October 7 and Israel's subsequent air and ground campaign in Gaza.
Hamas fired on an Israeli border community from the West Bank, a video released by Hamas on Wednesday showed.
Israel's Army Radio reported there were no casualties in Bat Hefer, a village located near the barrier that separates Israel and the occupied West Bank, but there was damage to property.
The attackers, who could be seen wearing Hamas headbands, came from a refugee neighbourhood in the Palestinian city of Tulkarm in the West Bank.
The Israeli army has repeatedly carried out raids in Tulkarm and other Palestinian towns and cities in the West Bank.
Since the start of the Gaza war following the Hamas massacre on October 7, the situation in the West Bank has grown more tense.
According to the Ministry of Health in the West Bank, around 500 Palestinians have been killed in Israeli military operations, confrontations or their own attacks since then. Israeli settlers have also taken violent action against Palestinians.
In Gaza, more than 36,100 people have been killed so far by Israel since the beginning of the war, according to the Hamas-run health authority.
The war is likely to continue at least until the end of the year, according to Israel's national security advisor.
"We can expect at least seven more months of fighting this year," Tzachi Hanegbi told the Israeli Kan channel. This was necessary to destroy Hamas' rule and military capabilities, he said.
The army had defined 2024 as the "year of fighting" in its plans, Hanegbi said. "We need staying power and stamina."
The border area between Egypt and the Gaza Strip had become a "smugglers' paradise" over the past 17 years, he added, saying together with Egypt, it was necessary to ensure that there was no more arms smuggling there in future.
Egypt has said a total of 1,500 tunnels in the border area had been destroyed since 2013.
Israel's advance into the corridor represents a further test for its relations with neighbouring Egypt. The two countries signed a peace treaty in 1979, establishing the corridor as a buffer zone.
Egypt in January said that an "occupation" of the corridor by Israel would be a violation of the treaty.
Hanegbi said that Israel was likely to maintain security control in the long term "because there are no other volunteers," adding that Israel is not seeking civilian rule in the coastal strip and hopes for a new Palestinian leadership.
For Israel, though, this would only be possible on the "day after Hamas."
The Israeli leadership continues to insist on its aim to eliminate the last battalions of Hamas.