Israel has been severely criticised by the European Union over the killing of 18 Palestinian civilians, with the EU's external relations chief saying the attack was "profoundly shocking".
EU's external relations chief, Benita Ferrero-Waldner
"The killing this morning of so many civilians in Gaza, including many children, is a profoundly shocking event," Benita Ferrero-Waldner said in a statement. "Israel has a right to defend itself, but not at the price of the lives of the innocent.
"It is very important for all parties to exercise utmost restraint and limit themselves to actions which are proportionate and in accordance with international humanitarian law," she added.
The strike on the town of Beit Hanoun was the deadliest in four years.
"At this critical juncture all sides have a responsibility to give dialogue a chance," Ms Ferrero-Waldner said in an appeal to kick-start the stalled peace process.
Minister for Foreign Affairs Dermot Ahern today said he was deeply concerned by the attack on Beit Hanoun, which had to be "unreservedly condemned."
"Ireland and the EU have regularly reminded all parties of their obligation to protect civilian lives. We have stated on many occasions that Israel has a right to defend itself against attack, but not at the expense of the lives and welfare of innocent civilians.
"An immediate end to all violence is now essential," he said after a meeting with the Secretary General of Amnesty International Irene Khan in London. "The only way forward for Israel and the Palestinians is the negotiation of a viable two-state solution. All parties have a clear duty to act now to revive a credible peace process, and avoid further appalling tragedies such as those witnessed in Gaza today."
Italy's foreign minister branded the killing a "massacre" and called for an urgent international initiative to stop the violence. "I think that now an international initiative to unblock the Palestinian situation is essential," Foreign Minister Massimo D'Alema told reporters.
"It is clear that if this escalation of violence is not stopped we risk returning to a climate of war," Mr D'Alema said.