Israeli Defence Minister Ehud Barak blamed Hamas on Friday for a blast along the Gaza border which wounded an Israeli soldier, and said he was mulling how and when to respond.
The blast, on a section of the border near the southern city of Khan Yunis, was claimed by the armed wing of the ruling Islamist Hamas movement and came hours after a Palestinian teenager was shot dead by Israeli troops in the same area, Palestinian medical officials and witnesses said.
"Israel views with great seriousness the detonation of an explosive tunnel along the border with the Gaza Strip, south of Kissufim," Barak said in a statement issued by his office early on Friday.
"Defence Minister Barak said that Israel sees Hamas as responsible for the incident and will examine how and when to respond."
The Israeli military said the blast had thrown an army vehicle 20 metres (66 feet) into the air, although no one was inside it at the time.
"During routine activity just inside the security fence, there was a large explosion that caused a vehicle to be thrown into the air. Luckily no one was in the vehicle at the time," a spokesman said.
A nearby soldier suffered minor injuries, probably from shrapnel, the spokesman said.
On Friday evening, Palestinians fired two rockets at southern Israel. A military spokesman told AFP that the projectiles exploded in the Eshkol region and "did not cause harm or damage."
It was not immediately clear whether the tunnel had been packed with explosives in order to attack Israeli troops, or whether it was a weapons cache which was detonated in order to avoid it being discovered by the army, military officials said.
Military spokeswoman Avital Leibovich said the blast had "left a crater which was five metres (17 feet) deep and four metres (13 feet) wide."
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"This tunnel is one of the most important discoveries in recent years. It contained a huge quantity of explosives," she told reporters late on Thursday.
She said a group of soldiers had gone some 200 metres (yards) into Gaza territory in order to dismantle explosive devices in the sector and were about to return when the blast hit.
"The explosion took place as the soldiers were getting ready to go back and fix a section of the fence which had been damaged," she said. "A military vehicle was thrown 20 metres into the air by the explosion."
The blast was claimed in a statement by Hamas militants from the Ezzedine al-Qassam Brigades who said they were responsible for "an attack with explosives which wounded a Zionist soldier."
Several hours earlier, Hmeid Abu Daqqa, 13, was killed by bullets fired from an Israeli helicopter in the same area, health ministry spokesman Ashraf al-Qudra told AFP.
"Thirteen-year-old Hmeid Yunes Abu Daqqa was killed by bullets fired from an Israeli helicopter during an incursion in Abasan and Al-Qarara," he said, referring to two neighbourhoods east of Khan Yunis.
Witnesses confirmed that Israeli helicopters had opened fire as tanks carried out an incursion, sparking a brief exchange of fire with militants.
A military spokesman on Friday confirmed troops had been operating in the area and had fired "towards open areas in the vicinity" after coming under attack by gunmen.
"During a routine activity west of Nirim, troops found a number of explosive devices and detonated them in a controlled manner. As a result of earlier fire toward them, they fired towards open areas in the vicinity," he said.
In recent weeks, militants have detonated several bombs against Israeli troops operating in the area east of Khan Yunis.
On October 23, a soldier was seriously hurt and two others lightly wounded by a device attached to a gate in the border fence. Four days earlier, a military vehicle and a section of the fence were damaged by another bomb.