The British Government is continuing to monitor the volatile situation in the Middle East amid more violence in Gaza and the prospect of an Israeli ground invasion.

There were reports of more air strikes on the coastal strip overnight with rockets targeting the headquarters of Hamas's leaders and other security compounds. It came after an unprecedented rocket attack aimed at the holy city of Jerusalem.

Prime Minister David Cameron and Foreign Secretary William Hague have urged both Israel and the Palestinians to make efforts to halt the violence. But they made clear they thought Hamas bears the greatest responsibility for the current crisis, as well as the ability to bring it most swiftly to an end.

In a telephone call with Israeli prime minister Benjamin Netanyahu, US president Barack Obama also repeated his country's support for Israel's "right to defend itself". Israel has put thousands of army reservists on stand-by and Mr Netanyahu has warned that his country is prepared to extend its operation against Hamas, sparking fears of a repeat of the ground incursion four years ago in which hundreds died.

Mr Cameron spoke by telephone with his Israeli counterpart on Thursday night to discuss the situation following Israel's assassination of Ahmed Jabari, the Hamas military chief, in a drone strike on his car on Wednesday. At least 30 Palestinians and three Israelis have died since the killing.

Downing Street said that the PM made clear that Hamas bears principal responsibility for the crisis, but called on Israel to do everything it could to avoid civilian casualties. The conflict has been intensifying over recent weeks, but flared up dramatically in the wake of the Israeli strikes against senior Hamas figures.

Mr Hague on Friday told BBC Radio 4's Today programme that there had been "a large increase" in rocket attacks on Israel from Gaza over recent weeks. And he added: "What Israel has done is obviously the Israeli response to that. The thing that would bring this most quickly to an end would be for Hamas to stop launching rockets at Israel.

"But of course, there are also responsibilities on Israel. I spoke to the Israeli foreign minister yesterday afternoon to urge the Israelis to do their utmost to reduce tension, to take every opportunity to de-escalate the situation and observe international humanitarian law, to avoid civilian casualties. Both sides have a responsibility to try to bring this to an end."

Shadow foreign secretary Douglas Alexander appealed to United Nations Secretary General Ban Ki-moon to go in person to the region for last-ditch talks to avert full-scale conflict.

"There is no military solution to the Israeli-Palestinian conflict. Over the decades violence has only led to more violence," he said.