BBC News with Marion Marshall

Palestinian militants in the Gaza Strip have fired a rocket into Jerusalem for the first time in decades as Israel continues its air attacks on the Gaza Strip. The Palestinian Group Hamas said it was aimed at the Israel’s parliament-the Knesset. Jon Donnison reports from Gaza.

The missile that Hamas says targeted Jerusalem was launched just 500 meters from the BBC office in the center of Gaza City. I watched as it rips deeply into dusk, heading northeast, towards the place both Israelis and Palestinians regarded as their capital. Minutes later, 50 miles or so away in Jerusalem, there were air-raid sirens. The city’s under rocket fire for the first time in decades. The missile fell short close to the West Bank of Israeli settlement al-Mali Amos. Israel’s biggest city of Tel Aviv was also targeted. It followed the day when Israel stepped up its air attacks on Gaza, hitting more than 300 targets.

Israel has sealed off roads around Gaza Strip, prompting speculation that it may be preparing a ground offensive. Twenty-seven Palestinians and three Israelis have been killed since Wednesday. The President of the Palestinian authority in Ramallah, Mahmoud Abbas, has urged Palestinians to unite in the face of what he called aggression by Israel.

This is an aggression against the whole Palestinian people. No one can claim that this is just about Hamas, or Islamic Jihad or Fatah. We must stand united, it’s vital that we exert maximum effort to achieve national unity and reconciliation.