The Israeli airforce has bombed the Hamas headquarters in Gaza on the fourth day of its offensive against the Palestinian group.
Hamas, the Islamist group that runs the Gaza Strip, said Israeli planes bombed the office building of Prime Minister Ismail Haniyeh and struck a police headquarters building.
An Israeli military spokeswoman confirmed the strike on Mr Haniyeh's office.
Israel earlier put 75,000 reservists on stand-by amid speculation of a ground invasion.
Overnight, Palestinians fired a rocket toward Jerusalem for the first time in decades.
At least 38 Palestinians and three Israelis have died since Hamas's military leader Ahmed Jabari was killed by an Israeli air strike on Wednesday.
Tel Aviv, Israel's commercial centre, also came under rocket attack, in defiance of an Israeli air offensive that began on Wednesday with the declared aim of deterring Hamas from launching cross-border attacks that have plagued southern Israel for years.
Hamas claimed responsibility for firing at Jerusalem and Tel Aviv.
Israel said the rocket launched toward Jerusalem landed in the occupied West Bank, and the one fired at Tel Aviv did not hit the city. There were no reports of casualties.
In a telephone call with Israeli Prime Minister Benjamin Netanyahu, US President Barack Obama repeated his country's support for Israel's "right to defend itself".
A White House spokesman said the two men also discussed options for "de-escalating the situation".
The BBC reports Israel blocked access to three major routes leading into Gaza on Friday; call-up papers have already been sent to 16,000 Israeli reservists, with officials authorising the mobilisation of another 75,000.
Analysts say it is the first time Gaza militants have deployed such powerful missiles.
Israel says its assault on Gaza is aimed at knocking out rocket-firing facilities.
A spokesman said on Friday it had destroyed Hamas's "nascent" unmanned aerial vehicles (UAV) programme.
Israel's army said on Friday that during the operation - codenamed Pillar of Defense - it had targeted "600 terror sites in Gaza, including underground rocket launchers & infrastructure".
It said 97 rockets fired from Gaza had hit Israel on Friday alone - 388 since Wednesday. Its radar defence system - Iron Dome - had intercepted 99 rockets.
Palestinian Authority President Mahmoud Abbas has accused Israel of carrying out "massacres".
United Nations Secretary-General, Ban Ki-moon has urged both sides to halt what he calls a dangerous escalation.
Egyptian leaders have promised to support Gaza against Israeli attacks. President Mohammed Mursi said on Friday that he would not leave Gaza on its own and condemned what he called Israel's blatant aggression hours after Prime Minister Hisham Qandil visited the area.