The Shin Bet recently arrested three Hamas militants from the Hebron area, who placed two explosives devices and planned to carry out additional attacks, according to information made public Thursday.
The three militants are suspected of placing the explosive devices in April with the intention of killing Israel Defense Forces troops in Halhul, north of Hebron in the West Bank.
Following their arrest, dozens of kilograms of explosives and other bomb-making materials were found in their possession.
One of the militants' brother, also a Hamas militant, was killed by IDF fire roughly two years ago.
Meanwhile, an Israeli air strike on Qassam rocket launchers in the northern Gaza Strip on Thursday injured at least two people, local residents said.
An IDF spokeswoman said earlier that an air strike was carried out but no one was in the area.
"There were several rocket launchers. One launched and at least one other rocket launcher was ready to launch," said an IDF spokesman.
Two Qassam rockets fired from the Gaza Strip Thursday morning landed in open areas in the western Negev. Two more rockets were fired Thursday afternoon, but where they struck could not be immediately identified.
Israel has rebuffed Palestinian Authority Chairman Mahmoud Abbas's call for a ceasefire under which Gaza militants would halt cross-border rocket attacks and Israel would stop its bombing campaign in the coastal strip.
Hamas, which formed a unity government with Abbas's Fatah faction two months ago, says any ceasefire must include an immediate end to all Israeli attacks in both Gaza and the West Bank, a demand rejected repeatedly by Israel.
Abbas has said he will meet Prime Minister Ehud Olmert on June 7. An Olmert spokeswoman said the upcoming talks were likely to take place in the West Bank city of Jericho.
Hamas and other militant groups have fired more than 270 rockets from Gaza, killing two Israelis, over the past two weeks.
Israel has hit back mainly with air strikes, killing nearly 50 Palestinians, most of them militants.
Two Palestinians were killed and two others wounded when a car exploded in the West Bank city of Nablus on Wednesday, witnesses and hospital officials said.
They said the casualties were men in their 20s. Their identities were not immediately known.
Nablus has seen frequent fighting between Palestinian militants and Israeli troops over the past 6 1/2 years of conflict. A military spokesman said he knew of no Israeli actions in Nablus at the time of the blast.
A local security source, who asked not to be identified, said Palestinian authorities were investigating whether the blast was caused by a bomb that went off prematurely.
Want to enjoy 'Zen' reading - with no ads and just the article? Subscribe todaySubscribe now