Israel is retaliating to a suicide bomb attack on a Jewish neighbourhood in Jerusalem.
Israeli helicopters have fired four missiles at Palestinian Authority headquarters and a small factory in Bethlehem.
The Israeli military say the strike was retaliation for the Jerusalem bombing which targeted worshippers and killed nine people.
An Israeli government spokesman said: "This has nothing to do with warfare, this has nothing to do with national liberation, this has to do with the murder of innocent Jews."
He added: "The state of Israel knows how to defend the people of Israel, and will do so."
Palestinian militants had vowed to attack after Israel's military stormed into two West Bank refugee camps over the past three days. Twenty-three Palestinians including gunmen, policemen and civilians as young as 10 have been killed in the camps since Thursday.
PA