The Israeli military says it has taken control of a strategic area on the Gaza-Egyptian border known as the Philadelphia Corridor.
An Israel Defense Forces (IDF) spokesman said some 20 tunnels used by Hamas to smuggle weapons into Gaza had been discovered there.
Egyptian television quoted sources as saying that Israel was trying to justify its military operation in the southern Gaza city of Rafah.
The news comes amid tense relations with Egypt.
“In recent days, IDF troops have established operational control of the Philadelphia corridor on the Egyptian-Rafa border,” IDF spokesman Rear Admiral Daniel Hagari said on Wednesday.
He described the corridor as a “lifeline” for Hamas, which “regularly smuggles weapons into Gaza.”
He said troops were “investigating… and eliminating” tunnels found in the area.
According to the New York Times, Hagari later briefed reporters and said he could not confirm whether all tunnels entered Egypt.
The Philadelphia Corridor is a buffer zone, only about 100m (330 feet) wide in parts, that runs along the Gaza side of the 13-kilometer (8-mile) border with Egypt.
Egypt has previously said it has destroyed cross-border tunnels, making any weapons smuggling impossible.
Al-Qahera News quoted “high-level” Egyptian sources as saying that Israel “uses these accusations to justify continued operations against the Palestinian city of Rafah and to prolong the war for political purposes”.
On October 7, Hamas launched an unprecedented attack on Israel, killing about 1,200 people and taking another 252 people hostage. Israel insisted that Rafah must win the war.
At least 36,170 people have been killed in Gaza since the conflict began, according to the Hamas-run health ministry.
Tensions between Egypt and Israel have increased since Israeli forces took control of the Gaza side of the Rafah crossing three weeks ago as part of an offensive against Hamas.
Earlier this week, An Egyptian soldier was killed in an incident involving Egyptian and Israeli troops in the border area near Rafah.
Egypt is a staunch supporter of the Palestinians and condemns Israel’s military operations in Gaza and its killing of thousands of civilians during the war.
Like Israel, Egypt has maintained a blockade on its border with Gaza since Hamas came to power in 2006.
However, Egypt has kept an open line with Hamas and has been acting as a mediator in on-again, off-again indirect negotiations between Israel and the group in an attempt to reach a ceasefire and release Israeli hostages held by Hamas in Gaza.
