A female suicide bomber has killed four Israelis in an explosion at the border with the Gaza Strip.
Israelis and Palestinians were among the wounded
Another seven people, including at least two Palestinians, were injured in the blast at the Erez crossing.
The bomber also died in the attack, which has been claimed by two Palestinian militant groups.
It is the first suicide bombing for almost three weeks and comes a day after militants killed a Jewish settler near the West Bank town of Ramallah.
The radical groups Hamas and the al-Aqsa Martyrs' Brigades, which has been linked to Palestinian leader Yasser Arafat's Fatah faction, jointly claimed the Erez bombing.
"For the first time [Hamas] used a female fighter and not a male fighter and that was a new development in resistance against the enemy," Hamas founder Sheikh Ahmed Yassin told Reuters news agency.
"Resistance will escalate against this enemy [Israel] until they leave our land and homeland."
The woman blew herself up inside a security office at about 1000 (0800 GMT) as Palestinians were going through security checks before entering a nearby industrial complex.
Israeli officials said the bomber tricked soldiers by saying she had a metal implant in her leg.
"Because she was a woman, a female soldier was sent for to search her. She used this opportunity to enter the building, a metre or two past the door, and blow up," said Israeli Brigadier-General Gadi Shamni, commander of Israeli forces in the Gaza Strip.
Witnesses described chaotic scenes as the woman detonated her explosives.
"Glass and black smoke flew everywhere," an unnamed Palestinian told Reuters news agency.
"Arabs were screaming, Jews were screaming, nobody knew what was going on."
Another witness said: "I heard soldiers screaming, the blast was very strong, and I saw one of the women [inside the security office]... bleeding from her legs."
Hamas and al-Aqsa Martyrs' Brigades identified the bomber as Hamas member Reem Raiyshi, a mother-of-two in her early 20s, from the Gaza Strip.
The Israeli Government said it might tighten measures against Palestinians following the bombing.
"The attack this morning is particularly shocking because as a gesture of goodwill, Israel allows Palestinian workers to come into Israel, and the Palestinian terrorist organisations took this opportunity in order to kill as many people as possible," said Israeli Government spokesman Avi Pazner.
"I presume that we will have to take measures in order to prevent that."
Erez is the main crossing point between Israel and the Gaza Strip, which is surrounded by an Israeli fence to stop suicide bombers entering Israel.
The blast is the first suicide attack since 25 December, 2003, when four Israelis were killed and over 20 injured in a blast near the Israeli city of Tel Aviv.
It came a day after a 29-year-old Jewish settler was killed by Palestinian militants in a drive-by shooting near the West Bank city of Ramallah.