Israel has bombed the Hamas-run Interior Ministry in Gaza and closed border crossings with the coastal strip in an intensified campaign to halt Palestinian rocket attacks.
The four-storey ministry complex in Gaza City was empty at the time but one woman was killed and at least 30 others nearby were wounded in the air strike, medical officials said.
"It felt like an earthquake," said Umm Fahmi, a woman who lives across from the blast site.
"My house did not only shake, it jumped from its foundations and back down. How could they drop such a bomb in a residential area on top of people's heads?" she said, peering through the dust at the concrete and steel remains of the security complex.
It was the first Israeli bombing of a Palestinian government building since Hamas Islamists took over Gaza in June after routing secular Fatah forces loyal to President Mahmoud Abbas.
An Israeli air strike minutes later damaged Hamas's naval headquarters in the central Gaza Strip but caused no casualties. A Hamas man died and several others were hurt in an attack on Jabalya, east of Gaza City, Hamas and hospital officials said.
Israel has killed at least 34 Palestinians in Gaza this week as part of what officials describe as a stepped-up campaign to pressure Hamas to rein in militants who have fired more than 110 rockets into the Jewish state in the last three days alone.
An Israeli army spokeswoman confirmed the first two air strikes and called the targets "Hamas terrorist" positions.
"This is part of our response to Qassam (rocket) fire against Israel," she said. There was no immediate Israeli comment on the Jabalya strike.
The Interior Ministry oversees Hamas-controlled government forces in Gaza but not the group's armed wing. The armed wing claimed responsibility for most rocket salvoes since Tuesday, when Israel killed 18 Palestinians, mostly Hamas militants.