GAZA -- The Israeli air force destroyed a Hamas security headquarters building in Gaza Thursday, killing at least one person.

Ynetnews reported that more than 30 people were wounded in the Gaza strike, which followed a barrage of Qassam rockets fired from Gaza into western Negev in Israel.

After the air force strike, Hamas threatened to use suicide attacks against Israel, Haaretz reported.

"This is an open war launched against Hamas. All options are open, including martyrdom operations," Abu Ubaida, a spokesman of Hamas' armed wing, told Haaretz.

Earlier, Israeli tanks had rolled into Gaza for the first time since a cease-fire was declared six months ago.

"We have had enough. Israel will take all defensive measures to protect our citizens from these Hamas rockets," Miri Eisin, a spokeswoman for Prime Minister Ehud Olmert, said before the air strike, Haaretz reported.

Olmert had supported a policy of restraint toward Hamas. A source told Haaretz that Olmert changed course upon learning that Hamas planned to escalate its attacks.

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