The Prime Minister announced an extra £3 million aid for Gaza today as he again called for an unconditional ceasefire to stop the conflict.

David Cameron said Britain had already given £7 million in aid but, questioned about the conflict at an event today, added: "And I can announce today we are going to give an further £3 million of aid to help make sure the people in Gaza have the basic necessities of life, the food, the shelter and the assistance that they need."

He again repeated the call for both Israel and Hamas to put down their weapons - but blamed Hamas for breaking ceasefires.

"We should be very clear that we want an unconditional, immediate, humanitarian ceasefire that applies to everybody," he said.

"What we are seeing happening in Gaza is completely tragic and ghastly, the loss of life is appalling, it is heart-rending watching these scenes on our television.

"But while calling for an unconditional, immediate ceasefire, we do have to be clear about a couple of points.

"Yes, it is awful what is happening in Gaza and the loss of life, but we do have to remember, whenever we have had a ceasefire in the last few days, it has been a ceasefire that has been obeyed and observed by the Israelis but it has not been observed by Hamas.

"Hamas continue the rocket attacks that are not aimed at military targets or political targets. They are aimed, indiscriminately, into Israel in order to do the maximum damage they possibly can.

"And so we do have to understand that that has to stop in order for there to be a lasting ceasefire."

The Prime Minister, speaking at a "Cameron Direct" question-and-answer session in Warrington, Cheshire, said he "worried" because the "facts on the ground" were "beginning to make a two-state solution impossible".

The extra £3 million he announced today will fund an emergency food programme for Gaza's 1.8 million population.

An estimated 1,200 Palestinians and 55 Israelis have been killed in the conflict.

Israel launched its offensive in Gaza after a surge in rocket fire from the territory.

Hamas, which controls Gaza, has said it will not stop fighting until a blockade on the area, maintained by both Israel and Egypt, is lifted.

Announcing the new aid, International Development Secretary Justine Greening said: "After more than three weeks of fighting, the death toll in Gaza is rising and more than 200,000 people, many of them children, have been displaced from their homes. We urgently need to stop the bloodshed: we continue to call for an unconditional and immediate humanitarian ceasefire to prevent any more needless suffering.

"The situation in Gaza is dire. The UK is helping to meet immediate needs, including with this latest contribution of £3 million which will get food to hundreds of thousands of vulnerable people.

"All sides must adhere to international humanitarian law, all feasible precautions must be taken to avoid harm to civilians, and all sides must allow aid agencies unimpeded access to get to those in desperate need."

Access to food is an increasing issue of concern in Gaza, with the United Nations reporting shortages and sharp increases in the prices of certain products.

Meanwhile, Foreign Secretary Philip Hammond appealed for an immediate ceasefire from both sides, but refused to say whether he regarded Israel's military action as a "disproportionate" response to the firing of rockets from Gaza.

Asked five times on BBC Radio 4's Today programme whether he thought Israel's military action was disproportionate, Mr Hammond said there would be a proper evaluation of the offensive "in the fullness of time".

His reticence on the issue contrasts with comments by Deputy Prime Minister Nick Clegg, who earlier this month accused Israel of imposing a "disproportionate form of collective punishment" on Gaza.

The Foreign Secretary initially said "disproportionate" was an "emotive word", before adding: "What Israel does in Gaza must be proportionate. That's a requirement of international law.

"It would not be legal if it was not proportionate."

Archbishop of Canterbury Justin Welby called for a renewed commitment to political dialogue from both sides in the conflict, warning that their current strategies are "self defeating".

And he described violence and abuse directed at Jewish people in the UK, which has risen since the outbreak of the current crisis, as "unacceptable".

In a statement released by Lambeth Palace, the Archbishop said: " While humanitarian relief for those civilians most affected is a priority, especially women and children, we must also recognise that this conflict underlines the importance of renewing a commitment to political dialogue in the wider search for peace and security for both Israeli and Palestinian. The destructive cycle of violence has caused untold suffering and threatens the security of all.

"For all sides to persist with their current strategy, be it threatening security by the indiscriminate firing of rockets at civilian areas or aerial bombing which increasingly fails to distinguish between combatants and non-combatants, is self-defeating.

"The bombing of civilian areas, and their use to shelter rocket launches, are both breaches of age-old customs for the conduct of war. Further political impasse, acts of terror, economic blockades or sanctions and clashes over land and settlements, all increase the alienation of those affected.

"Populations condemned to hopelessness or living under fear will be violent. Such actions create more conflict, more deaths and will in the end lead to an even greater disaster than the one being faced today. The road to reconciliation is hard, but ultimately the only route to security. It is the responsibility of all leaders to protect the innocent, not only in the conduct of war but in setting the circumstances for a just and sustainable peace."

He added: "While it is acceptable to question and even disagree with particular policies of the Israeli government, the spike in violence and abuse against Jewish communities here in the UK is simply unacceptable. We must not allow such hostility to disrupt the good relations we cherish among people of all faiths. Rather we must look at ways at working together to show our concern and support for those of goodwill on all sides working for peace."

The Archbishop of Canterbury, the Most Rev Justin Welby, condemned a "destructive cycle of violence" which had caused "untold" suffering and threatened the security of all.

"For all sides to persist with their current strategy, be it threatening security by the indiscriminate firing of rockets at civilian areas or aerial bombing which increasingly fails to distinguish between combatants and non-combatants, is self-defeating," he said.

"The bombing of civilian areas, and their use to shelter rocket launches, are both breaches of age old customs for the conduct of war.

"Further political impasse, acts of terror, economic blockades or sanctions and clashes over land and settlements, all increase the alienation of those affected.

"Populations condemned to hopelessness or living under fear will be violent. Such actions create more conflict, more deaths and will in the end lead to an even greater disaster than the one being faced today.

"The road to reconciliation is hard, but ultimately the only route to security.

"It is the responsibility of all leaders to protect the innocent, not only in the conduct of war but in setting the circumstances for a just and sustainable peace."

He added that while it was "acceptable" to question and even disagree with particular policies of the Israeli Government, the recent spike in violence and abuse against Jewish communities in the UK was "simply unacceptable".

"We must not allow such hostility to disrupt the good relations we cherish among people of all faiths," he said.

"Rather we must look at ways at working together to show our concern and support for those of goodwill on all sides working for peace."