The UN Security Council held another emergency meeting on Wednesday about the worsening hostilities between Israel and Palestinians, again without agreeing on a joint statement due to opposition from the United States, Israel's key ally, according to diplomats.

The United States saw the Security Council meeting as a sufficient show of concern, one diplomat told AFP on condition of anonymity.

"The US doesn't see that a statement will help de-escalate," said another.

According to several sources, 14 of the 15 members of the council were in favour of adopting a joint declaration aimed at reducing tension.

The US mission to the UN was not immediately available for comment.

UN Middle East envoy Tor Wennesland warned the meeting that the "situation has deteriorated since Monday... there is a risk of a spiral of violence," according to a diplomatic source.

During a first emergency meeting on Monday, the United States also refused to back a text proposed by Tunisia, Norway and China calling on all parties to refrain from provocation.

Renewed rocket fire and rioting in mixed Jewish-Arab towns have fuelled growing fears that deadly violence between Israel and Palestinians could descend into full-scale war.

The most intense hostilities in seven years have killed at least 53 people in Gaza, including 14 children, and six in Israel, including an Israeli soldier and one Indian national, since Monday.