A Hamas official has said that the anticipated announcement of a Gaza truce agreement with Israel has been delayed.

Ezzat al-Rishq told Reuters news agency that there would be no announcement until Wednesday.

"The Israeli side has not responded yet, so we will not hold a [news] conference this evening and must wait until tomorrow," said Rishq.

"The truce is now held up because we are waiting for the Israeli side to respond."

Another Hamas official, Ayman Taha, had earlier told Reuters that the truce would be declared and in effect by 22:00GMT on Tuesday night.

There was no immediate Israeli comment on the Hamas statement or on the prospect of a ceasefire, although an Israeli spokesperson has said the deal is not quite finalized.

US Secretary of State Hillary Clinton arrived in Jerusalem on Tuesday night and met Israeli Prime Minister Binyamin Netanyahu.

In a press conference with Netanyahu, Clinton re-iterated the US commitment to the Israeli government.

"President Obama asked me to come to Israel with a very clear message: America’s commitment to Israel’s security is rock-solid and unwavering. That is why we believe that it is essential to de-escalate the situation in Gaza," said Clinton.

"The rocket attacks from terrorist organizations from inside Gaza on Israeli cities and towns must end, and a broader calm restored. The goal must be a durable outcome that promotes regional stability and advances the security and legitimate aspirations or Israelis and Palestinians alike."

Clinton is expected to meet with Palestinian President Mahmoud Abbas on Wednesday. She will not be meeting Hamas officials.

Al Jazeera's Peter Greste, reporting from Cairo, said that it is best to approach the news of an imminent truce deal with caution.

"It's one thing for this agreement to be signed, it's quite another for it to be implemented," said Greste.

"But here's what we do understand is to be contained in this agreement: Firstly, that Israel has agreed to stop targeted assassinations of Hamas leaders. Secondly, that Hamas has agreed to stop firing rockets over the border into Israel," said Greste.

"Thirdly, that the border restrictions into Gaza will be eased, but we don't know quite what that means - we don't know what restrictions will be lifted."

He added that Egypt would be the guarantor of the agreement.

The terms of the truce, first hinted at by Egyptian President Mohamed Morsi, have not yet been disclosed. Egypt has been trying to negotiate a ceasefire with the help of Qatar and Turkey.

Al Jazeera's Nisreen El-Shamayleh, reporting from Jerusalem, said that Israeli media outlets have been quoting unnamed officials who say that Clinton will announce a ceasefire agreement negotiated by the US, Egyptian and the European Union.

"This kind of goes along with what we've heard coming out of Cairo, with the newly-elected president, Mohamed Morsi, hinting to journalists that a ceasefire is imminent," said El-Shamayleh.

US President Barack Obama called Morsi for the third time in 24 hours on Tuesday to "commended" his efforts to secure a ceasefire in Gaza, the White House said.

"He commended President Morsi's efforts to pursue a de-escalation" in the Gaza Strip, said Ben Rhodes deputy national security advisor.

UN Secretary-General Ban Ki-moon held talks with Netanyahu in Jerusalem on Tuesday.

"Regrettably, I'm back again in the region only nine months since my last visit, because of violence in Israel and Gaza...the world is extremely concerned at the rising loss of human lives," Ban said.

He will also meet Abbas to discuss the crisis.

Earlier on Tuesday, Ban met the Arab League chief, Nabil el-Araby, in Cairo and called for support for Morsi's efforts to mediate a truce in the conflict.

A delegation of nine Arab ministers, led by Mohamed Amr, Egyptian foreign minister, visited Gaza in a further signal of heightened Arab solidarity with the Palestinians.

El-Araby said a ceasefire is not the the real issue facing Gaza.

"The real problem is not a truce. The real problem that the Arab and Islamic countries and all friendly countries in the world must focus on is ending the occupation," said el-Araby.

The United Nations Security Council, meanwhile, is due to hold a session on the crisis in Gaza on Wednesday at 15:00 GMT.

The Israeli army has killed at least 130 Palestinians in more than 1,450 attacks on Gaza since last Wednesday.

Since then, 760 rockets fired by Palestinian fighters have hit Israel while about 400 others have been intercepted by Israel's anti-missile system.

More than 920 Palestinians have been seriously injured, including and women and children.

Four Israeli civilians and one Israeli soldier have been killed in the conflict that has also left dozens of Israelis injured.

PHOTO CAPTION

Israel's Prime Minister Benjamin Netanyahu delivers joint statements with U.S. Secretary of State Hillary Rodham Clinton (not seen) in Jerusalem, Tuesday, Nov. 20, 2012.

Aljazeera