Saudi Arabia yesterday blamed Hamas for Israel's continuing offensive in the Gaza Strip and urged it to resolve bitter differences with the western-backed Palestinian Authority - even as divisions deepened with a new charge of treachery.

Arab League foreign ministers meeting in emergency session in Cairo warned it was not possible to help until the Islamist movement in control of Gaza returned to national unity talks with its rival Fatah.

A furious Hamas attacked the Arab League stance as "pathetic". Spokesman Fawzi Barhoum also accused Mahmoud Abbas, the Palestinian president, of ordering members of Fatah in Gaza to gather intelligence on the whereabouts of Hamas leaders to pass to Israel - a grave charge that underscores the deep rift between the factions.

Discussions between Arab states were sharp too, amid bickering over calls for an emergency summit conference in Qatar tomorrow .

"Everyone is watching as the intensity of Arab-Arab disputes increase," warned the league's secretary general, Amr Moussa.

"We must close ranks and stop pouring oil on the fire."

Moussa advised the Palestinians to demand a ceasefire resolution from the UN security council despite the clear risk that it would be vetoed by the US. Hamas spokesman Sami Abu Zuhri scorned the Arab position as "weaker than statements issued by the EU".

Diplomats reported that with demonstrations across the Arab world, pressure is growing to freeze or withdraw an important peace offer to Israel in protest against the Gaza onslaught.

Syria and Gulf maverick Qatar want a summit. But they met fierce resistance from Saudi Arabia and Egypt, the western-backed Arab states that are most hostile to Hamas. This week Syria suspended its own indirect talks with Israel.

Fourteen of the league's 22 members are required for a summit to be convened. "The Egyptians don't want their role to be exposed," said an Arab diplomat. "That's why they don't want the summit."

Jordan, which has a large Palestinian population, is keeping a lower profile. Egypt is under attack, especially by Lebanon's Hizbullah movement, for refusing to open the Rafah border crossing point at the southern end of the Gaza Strip.

Saudi Arabia did not name Hamas, but it was clear who was being blamed for having provoked Israel's attacks by failing to renew a shaky six-month ceasefire when it expired on 19 December.

"This terrible massacre would not have happened if the Palestinian people were united behind one leadership," Saudi foreign minister, Prince Saud al-Faisal told the Palestinians.

"Your Arab brothers cannot extend to you the hand of real help, if you do not extend the hand of affection to each other," he added, urging Hamas and Fatah to form a national unity government.

As the Cairo talks took place, Egyptian riot police nearby beat back thousands of protesters - many from the outlawed Muslim Brotherhood - shouting slogans in support of the people of Gaza.

Western diplomats fear the league may withdraw its Arab Peace Initiative, unveiled in 2002 and endorsed in 2007. The plan, seen by most governments - including the incoming US administration - as the most promising basis for comprehensive Middle East negotiations, offers Israel the recognition of all Arab states if it withdraws to the 1967 borders and agrees to an independent Palestinian state.

Iran's president Mahmoud Ahmadinejad, an ally of Syria and Hamas, called on Arab leaders to act quickly to end the Israeli attacks.

As diplomats struggled to keep up with events on the ground, the Turkish prime minister, Recep Tayyip Erdogan, flew to Syria for talks with President Bashar al-Assad.

Erdogan denied planning to meet Khaled Mashal, the exiled Hamas leader, before flying to Jordan and Saudi Arabia.