JERUSALEM — Israel’s military said it found another tunnel on Thursday burrowed from Gaza into Israeli territory — the second in three weeks — as officials revealed the arrest last month of a Hamas operative who had disclosed “much information” about the group’s digging.

The Israeli effort to find tunnels from Gaza, which Hamas considers a strategic asset, has led to a flare-up of violence along the border in recent days. Hamas militants have fired at Israeli forces along the border for the first time since a cease-fire brokered by Egypt ended 50 days of fierce fighting in the summer of 2014. The Israelis responded with tank fire and airstrikes. Medical officials in Gaza said that a Palestinian woman, identified as Zayna Al-Amur, 55, was killed by Israeli shelling in the southern Gaza Strip, according to Wafa, the official Palestinian news agency.

The Hamas operative under arrest, Mahmoud Atawneh, 29, was detained in early April after he crossed the border fence into Israel armed with two knives, according to Shin Bet, Israel’s domestic security agency.

The Shin Bet announcement fueled speculation over whether Israel’s recent success in detecting tunnels was the result of a tip, rather than some unique technological breakthrough as Prime Minister Benjamin Netanyahu of Israel had suggested last month.