Israel killed nine Hamas militants in the Gaza Strip on Tuesday and the group's armed wing issued a formal statement claiming responsibility for its first suicide bombing in Israel since 2004.
Seven of the Hamas men were killed by an Israeli air strike on a security compound in southern Gaza and two other armed members of the movement were shot dead by Israeli soldiers near the border with Egypt.
Hamas's Izz el-Deen al-Qassam Brigades issued a statement claiming "full responsibility" for Monday's suicide bombing in the southern Israeli desert town of Dimona. An Israeli woman was killed along with a Palestinian suicide bomber and another attacker who was shot dead by police.
Hamas identified the two attackers as Mohammed el-Herbawi and Shadi Zoghbor, both from the West Bank city of Hebron. A Hamas source told Reuters on Monday that the group was responsible for the Dimona attack but a formal statement was not issued until Tuesday.
"I never expected Mohammed to carry out a martyrdom attack. He was quiet and normal. I was shocked when I saw his name on ... television," his weeping mother, Um Samer, told Reuters. Hamas's claim of responsibility, and the sound of Israeli jets and drones overhead, raised fears in the Hamas-controlled Gaza Strip of an intensive Israeli military campaign in retaliation for Monday's bombing.
A senior member of Prime Minister Ehud Olmert's party, Tzachi Hanegbi, urged the Israeli government to step up its fight against Hamas, which took over Gaza in June, by assassinating the group's political leaders.
Hamas officials said the men killed in the security compound were holding afternoon prayers when the missile struck. The Israeli military said the air strike was in response to Palestinian rocket attacks on southern Israel.
A Hamas security officer said its members were ordered to take "all necessary precautions", including turning off cellular phones that could be tracked by Israeli drones that routinely fly over the Gaza Strip.
Hamas opposes Palestinian President Mahmoud Abbas's peace talks with Israel, but top Israeli and Palestinian negotiators, who met on Monday after the Dimona bombing, have vowed not to be deterred by the violence.
Israel assassinated Hamas leaders Ahmed Yassin and Abdel Aziz al-Rantissi in the Gaza Strip in 2004, killings that Hanegbi said had a "direct effect on the motivation of the Hamas leadership to continue to carry out suicide attacks".
The Israeli military has since largely refrained from targeting Hamas's political wing but has struck repeatedly against the Islamist movement's field commanders.
"(Hamas's political leaders) have evidently forgotten the bitter fate (of Yassin and Rantissi) and therefore we should add the current leaders of the organisation to that list," Hanegbi said.
"There is no difference between those who wear a suicide suit and a diplomat's suit," he said. "Both are carrying out ... war crimes and we should exact the full price not only from the minor squads in the field but also from those who send them."