In a statement, the EU urged Israel to halt activities that endanger civilians saying they were "contrary to international law."

It also called for an immediate end to Palestinian rocket attacks on Israeli territory and insisted that the peace process should not be interrupted.

"The (EU) presidency condemns the recent disproportionate use of force by the Israeli Defense Forces against (the) Palestinian population in Gaza and urges Israel to exercise maximum restraint and refrain from all activities that endanger civilians. Such activities are contrary to international law," said the statement issued by the Slovene government on behalf of the EU.

Slovenia currently holds the EU's rotating presidency.

The tough wording reflects shock at the high number of civilian casualties and frustration that the escalation of violence in the Middle East risks derailing peace efforts yet again.

"The Presidency rejects collective punishment of the people of Gaza. We are deeply worried about the suffering of the civilian population on (the) Israeli and Palestinian side," the EU added. "We have stated too many times that both Israelis and Palestinians deserve to live in peace and security."

The EU, "reiterates condemnation of continued firing of rockets into Israeli territory and calls for its immediate end."

As Israel threatens a ground offensive and the Palestinians threaten to pull out of peace talks, the EU appealed to both sides to stick to the peace plan drawn up in Annapolis, Maryland, in November.

"The peace process should not be interrupted. Actions that undermine this process should be stopped immediately," the statement said. "The Presidency urges all sides to advance on the path to a negotiated settlement of the Israeli-Palestinian Conflict as set out in Annapolis."