Israel's military said Monday it had located and destroyed a tunnel extending from the Gaza Strip into Israeli territory, in the first such discovery since a devastating 2014 conflict.
Israeli Prime Minister Benjamin Netanyahu called it a "global breakthrough in the ability to locate tunnels".
Military spokesman Peter Lerner said the tunnel he accused the Islamist group Hamas of building extended from the southern Gaza Strip several hundred metres (yards) into Israel, although no exit had been constructed.
He declined to provide specifics on how it was "neutralised".
"This tunnel is the first one to be found since Operation Protective Edge," Lerner told journalists, referring to the 2014 war.
"It was built by Hamas in order to infiltrate and execute terror attacks against the people of the southern communities and (military) forces in that area."
Hamas's military wing called the discovery, which it said was east of the southern Gazan city of Rafah, "only a drop in the ocean of what the resistance has prepared in order defend our people, the freedom of the holy places and its land and captives".
The Ezzedine al-Qassam Brigades also claimed the army had not "dared" to publish the full details of the tunnels for fear of scaring Israelis.
According to Lerner, the tunnel was 30 to 40 metres underground and large enough for an adult to stand inside.
- New technology -
It included concrete slabs, "communication lines" and rails used to move rubble, he said.
Lerner called it a "new tunnel", saying the military believed it was built after the 2014 war.
Hamas forces have used tunnels in the past to avoid or carry out attacks, store weapons and at times to enter Israel and capture soldiers.
Israel has suggested in recent months it has developed new technologies that will help it locate Hamas tunnels, and Netanyahu implied the find was the result of this.
"Israel has achieved a global breakthrough in the ability to locate tunnels," he said in a statement. "The government is investing considerable capital in countering the tunnel threat. This is an ongoing effort that will not end overnight."
Daniel Nisman, security analyst with the Israeli risk analysis firm Levantine Group, said if the technology had made the difference "that is bad news for Hamas".
Israel launched its 2014 operation in Hamas-run Gaza with the stated objectives of halting rocket fire and destroying attack tunnels into Israel.
During the war, 32 tunnels were discovered, including 14 that extended into Israel, according to a UN report on the conflict.
It was the third war in Gaza since 2008 and the longest, deadliest and most destructive.
It killed 2,251 Palestinians, while more than 10,000 were wounded and 100,000 were left homeless.
- Tunnel collapses -
On the Israeli side, 73 people were killed, of whom 67 were soldiers. Up to 1,600 were wounded, according to the United Nations.
A UN report in June said both Israel and Palestinian militants may have committed war crimes during the conflict, decrying "unprecedented" devastation and human suffering.
There have been a number of tunnel collapses within Gaza in recent months, including those extending toward Egypt. Several Gazans have been killed.
The tunnels from to Egypt are generally used for smuggling into and out of the Gaza Strip, which is under an Israeli blockade. Egypt's border with Gaza has also remained largely closed.
In 2014, Egypt began setting up a buffer zone on its border with Gaza, and destroyed hundreds of tunnels it says were used to smuggle weapons and other items.
In September 2015, Egyptian forces carried out excavations that Palestinians say caused the flooding of the last remaining tunnels there.
An Israeli military official said flooding cannot be employed because of the large amount of territory along the Israeli-Gaza border and sea water that would be used would damage a reservoir in the area.
Lieutenant Colonel Ohad Bachar, head of training for an Israeli military engineering unit involved in destroying such tunnels, told AFP last week that the flooding option had been considered in the past, but was abandoned because of those concerns.
He said that in general, heavy equipment and explosives can be used to destroy tunnels.
"We are always... getting new ways to deal with this kind of threat," Bachar said.
