An Israeli helicopter fired a missile into the empty office of Palestinian Prime Minister Ismail Haniyeh today in an apparent signal the Hamas leader could be targeted unless militants released an abducted soldier.
The air strike was part of a military offensive in the Gaza Strip that has been coupled with statements from Israeli leaders that no one in the Hamas-led government should believe he was immune from attack.
"We will strike anyone who harms the citizens of Israel. No one will go unpunished," Israeli Prime Minister Ehud Olmert told his cabinet in broadcast remarks, without mentioning Haniyeh by name.
Mr Haniyeh was not in the office at the time of the strike, witnesses said. He arrived quickly to survey the damage.
"This is the policy of the jungle and arrogance," Mr Haniyeh said.
One Hamas member was killed in a second attack on an office used by forces loyal to the Islamic militant group, whose charter calls for Israel's destruction.
A third strike hit a Hamas school, but there were no casualties. Israel, which pulled out of the Gaza Strip last year, sent troops and tanks into the south of the territory on Wednesday after Palestinian gunmen, some from the armed wing of Hamas, seized Corporal Gilad Shalit in a cross-border raid a week ago.
"I have ordered the military and defence officials to use their power and wisdom to pursue these terrorists, and those who depatch them, provide their ideology and sponsor them," Mr Olmert said. "I reiterate - no one will be exempt."
Israel last assassinated top Hamas leaders in 2004, killing Sheikh Ahmed Yassin and Abdel-Aziz al-Rantissi.
With a Palestinian humanitarian crisis looming, Israel reopened Karni, the main commercial crossing into the Gaza Strip, and witnesses said fuel shipments began rolling across the frontier.
Following Shalit's abduction, Israel announced Gaza crossings would be closed. It also launched air strikes against Gaza's main power plant and road bridges and arrested senior Hamas politicians in the occupied West Bank.
Serious casualties have so far been limited to two dead militants.
Even before the standoff, the Palestinian government was straining under a US-led economic embargo imposed to get it to recognise Israel, renounce violence and accept past interim peace deals.
Palestinian President Mahmoud Abbas and Egyptian mediators have been involved in round-the-clock negotiations with Hamas in an attempt to defuse a standoff that has plunged relations with Israel to new lows and dashed hopes of renewed peace talks.
A Palestinian official quoted mediators as saying 19-year-old Shalit was alive after being treated for wounds.