GAZA CITY -- A gunfight and an Israeli airstrike left four Palestinian militants dead in the Gaza Strip early Friday, according to Palestinian reports.
In addition, five Israeli soldiers were injured in an explosion along the border in the operation that preceded the airstrikes, military sources in Israel said.
According to a statement from the Israeli army, military engineers were trying to collapse a segment of a "terror tunnel" exposed last month leading from the Gaza Strip into southern Israel when Palestinian militants detonated a bomb targeting the Israeli forces, injuring five soldiers.
After the incident, Israeli aircraft targeted another tunnel in the southern part of the strip. Palestinian sources reported an additional three members of Hamas killed in the strike in Khan Younis.
Tweets from Israel's military accused Hamas of violating understandings reached after the 2012 eight-day military campaign in Gaza that Israel called Operation Pillar of Defense. The military also held Hamas responsible for all activities targeting Israeli civilians and soldiers.
Last month, Israeli forces exposed the tunnel, a milelong passage dug around 60 feet underground and leading from Gaza into Israel, emerging by the kibbutz of Ein Hashlosha.
Complete with electricity and transport infrastructure and layered with about 25,000 concrete slabs, the tunnel took over a year to prepare for use in a future cross-border attack, officials said.
A less massive underground passage was used by Palestinian militants in 2006 to attack an Israeli army post and abduct Gilad Shalit to the Gaza Strip, where he was held for over five years until being released in a 2011 exchange with Hamas in return for more than 1,000 Palestinian prisoners.
After the most recent discovery, Defense Minister Moshe Yaalon said the tunnel proves that Hamas is still preparing for a confrontation with Israel. Recently, Israel's army chief of staff, Benny Gantz, warned that the next round of combat could start with the detonation of such a tunnel.
[For the Record, 7:12 a.m. PDT Nov. 1: An earlier version of this post incorrectly gave the dateline as Gaza City, West Bank. Gaza City is in the Gaza Strip.]
Sobelman is a news assistant in The Times' Jerusalem bureau. Rushdi Abu Alouf is a special correspondent.