Syria's conflict has killed more than 320,000 people, uprooted more than half the population and left much of the country in ruins since it erupted almost six years ago.

The release of Egypt's ex-president Hosni Mubarak approved on Monday ends "talk of the Arab Spring" uprising that toppled him in 2011 after 30 years in power, an analyst said.

A British activist who advocates boycotting Israel over its occupation of Palestinian territory has been denied entry to the country, authorities said Monday.

Syrian rebel factions will not attend a new round of negotiations with government figures in the Kazakh capital, an opposition delegation spokesman told AFP on Monday.

"Rebel groups have decided not to participate in Astana," said Osama Abu Zeid, adding that one reason for the boycott was "unfulfilled pledges related to the cessation of hostilities."

Iraqi forces said Monday they had taken more territory from the Islamic State group as they press an offensive that has seen them recapture a third of west Mosul and trap jihadists inside.

A renewed push launched on March 5 has forced IS out of several neighbourhoods and key sites, including the main local government headquarters and the famed Mosul museum, tightening the noose around fighters there.

Syria's war has killed just over 320,000 people since it erupted six years ago, a monitor said Monday, noting that a fragile ceasefire had helped to slow the rising death toll.

The Britain-based Syrian Observatory for Human Rights said it had recorded the deaths of 321,358 people since the conflict broke out in March 2011 with protests against President Bashar al-Assad. 

Saudi Arabia's powerful Deputy Crown Prince Mohammed bin Salman, seeking foreign investment in an economic reform plan, left for the US Monday to meet President Donald Trump, state media said.

Prince Mohammed will be the highest-ranking Saudi official to hold talks with Trump since the US leader took office in January. 

Iran's Foreign Minister Mohammad Javad Zarif accused Israel's Benjamin Netanyahu of ignorance about history and the Jewish faith on Monday after he said ancient Persian rulers tried to destroy the Jews.

In a meeting with Russian President Vladimir Putin in Moscow, Netanyahu said Persia had made "an attempt to destroy the Jewish people that did not succeed" some 2,500 years ago, an event commemorated by the Jewish holiday of Purim over the weekend.

Israeli police Monday killed a Palestinian who attacked and wounded two border guards with a knife near an entrance to the old city of Jerusalem, police said.

The attacker, who was a resident of occupied East Jerusalem, entered a border guard post and wounded the two before being shot dead. One of the guards was seriously injured, the other more lightly, police added. 

At least 652 children were killed in Syria in 2016, making it the worst year yet for the country's rising generation, the United Nations' child relief agency said Monday.

There was no letup to attacks on schools, hospitals, playgrounds, parks and homes last year as the Syrian government, its opponents and the allies of both sides showed callous disregard for the laws of war.