The Shin Bet, Israel’s internal security agency, confirmed Thursday that it arrested a leading Hamas tunnel expert last month.

Mahmoud Atawnah, a member of Hamas’ Izz ad-din al-Qassam Brigades, was arrested after he crossed into Israel armed with two knives. Atawnah later told interrogators that he intended to kill the first Israeli he encountered.

Atawnah identified several fellow Hamas members to interrogators and described the group’s network of tunnels—where they were located, which materials were used in their construction, and their hidden entrances in private homes and institutions. He also shared information on the complicated system of living spaces and other amenities built into the tunnels. It was also revealed that Atawnah had stockpiled weapons in his home, including IEDs, rifles, and suicide belts.

The Shin Bet said Atawnah was one of several Hamas members currently under interrogation.

The IDF revealed today that it had uncovered a second tunnel extending into Israeli territory in three weeks. When the existence of the first tunnel was revealed, Palestinian media reported that Israel had captured a leading Hamas tunneling operative.

Israeli troops working to uncover and destroy the latest tunnel were fired upon on Wednesday by Hamas and Palestinian Islamic Jihad. No Israelis were injured. Firing on Israeli troops continued Thursday. A retaliatory response from an Israeli tank reportedly killed a Palestinian woman. The IDF stated that there were incidents of gun or mortar fire on Israeli troops since Tuesday.

“Terrorist elements in the Gaza Strip need to know that if they try to disrupt our lives, they will be delivered a severe blow,” Israeli Defense Minister Moshe Ya’alon said at a service commemorating the end of Holocaust Remembrance Day. “We will not tolerate a return to a routine of shooting and attempts to harm our civilians and soldiers. We will take firm action with an iron fist, as we have in the past few days, against the terrorist organizations in the Strip, led by Hamas, which is responsible for the shooting and incidents in Gaza.”

At least twelve Palestinians have reportedly been killed this year building the tunnels, which have been used to ferry attackers into Israeli territory as well as smuggle goods and weapons. Israel Radio reported last month that Hamas pays over 1,000 operatives to build tunnels and “invests hundreds of thousands of dollars each month in digging activities.”

Israeli border security intercepted a shipment of four tons of ammonium chloride, which can be used in the manufacture of rockets, at the Nitsana border crossing earlier this week. The chemicals had been hidden in a 40-ton shipment of salt.

[Photo: Shin Bet ]