Israel bombed the Hamas-run Interior Ministry in Gaza and closed border crossings with the coastal strip on Friday 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.