Syria's ceasefire "will not hold out", a senior rebel official in Aleppo warned on Saturday, as air strikes and shelling continued in some places and promised aid deliveries failed to come through.

Turkish police have detained more than 20 Islamic State suspects, including a Syrian man believed to be organising an attack in Istanbul, a local newspaper reported on Saturday.

The spotlight will be on Syria when world leaders gather at the United Nations next week as the United States and Russia try to shore up a fragile truce deal and President Barack Obama pushes for a boost in global refugee aid.

A Palestinian stabbed an Israeli soldier Saturday in the flashpoint West Bank city of Hebron before he was shot dead, the army said, in the fourth attack on Israelis in less than 24 hours.

Middle East economies have plunged into decline in the years of war since the Arab Spring, creating daunting economic and development challenges, according to an IMF report released yesterday.

The rubble-strewn Castello Road, the main route for humanitarian assistance into the divided Syrian city of Aleppo.

Israeli forces shot dead three Arabs in separate incidents in East Jerusalem and the West Bank yesterday, police and the military said, in a flare-up of a nearly year-old wave of unrest.

The United States and Russia said yesterday they wanted to extend the four-day-old ceasefire in Syria they have co-sponsored, although the agreement looked increasingly shaky, undermined by sporadic violence and a failure to deliver aid.

Israeli forces shot dead three Arab assailants in separate incidents in East Jerusalem and the West Bank on Friday, police and the military said, in a flare-up of a nearly year-old wave of Palestinian street attacks.

Air strikes and clashes tested a fragile ceasefire in Syria on Friday as civilians waited for aid and the UN Security Council was to discuss whether to endorse the US-Russian truce.

The Kremlin said on Friday it was using its influence to try to ensure the Syrian army fully implemented a shaky ceasefire agreement and that it hoped the United States would use its own influence with rebel groups too.

Fierce fighting and clashes between regime forces and rebels rocked the eastern edge of Syria's capital on Friday, an AFP correspondent and military source said, despite a fragile truce across the country.