Russia's envoy to the UN on Friday warned long-term ally President Bashar al-Assad over his vow to retake all of Syria, saying he faced dire consequences if he did not comply with Moscow over the peace process.

"Russia has invested very seriously in this crisis, politically, diplomatically and now also militarily," Vitaly Churkin told Kommersant daily, referring to an international agreement to cease hostilities sealed in Munich last week.

The Egyptian branch of the Islamic State group has posted pictures online of what it says was the execution of two men caught spying for the army in the Sinai.

One of those decapitated was presented by the IS offshoot Sinai Province as a "spy for the military intelligence" services, while it said the other was a "spy for the army".

Republican presidential hopeful Donald Trump says the invasion of Iraq was possibly the worst decision made by a U.S. president but acknowledged he may have initially supported the move.

"Bottom line, there were no weapons of mass destruction," Trump said during a town hall meeting hosted by CNN that saw the GOP frontrunner take questions from an audience in South Carolina ahead of the state's primary on Saturday. 

The Palestinians on Thursday welcomed an initiative put forward by France to hold an international Middle East peace conference, a proposal which Israeli Benjamin Netanyahu has dismissed.

"We definitely welcome the French initiative, we see it as a major possibility for challenging the status quo," Hossam Zomlot, an adviser to Palestinian President Mahmoud Abbas, told reporters. 

U.N. Secretary-General Ban Ki-moon is urging Syria's warring sides and the countries backing them to turn away from the "bankrupt logic of a military victory" and work to find a peace settlement, according to a report to the Security Council.

Ban warned that the recent upsurge in fighting in northern Aleppo province risked derailing efforts by U.N. envoy Staffan de Mistura to convene a new round of peace talks on February 25.

The Pentagon has asked Russia to stay away from parts of northern Syria where U.S. special operations forces are training local fighters to combat the Islamic State group, military officials said Thursday.

The acknowledgement Russia knows approximately where the highly covert U.S. commandos are based is significant because the Pentagon has repeatedly stressed it is not cooperating with Moscow as the two powers lead separate air campaigns in war-ravaged Syria.

Egypt's political and religious elite turned out Thursday for the funeral of former U.N. secretary-general Boutros Boutros-Ghali, who steered the world body through several global conflicts during one of its toughest periods.

The Egyptian diplomat, who became the first African secretary-general in 1992, died in Cairo on Tuesday aged 93. 

Russia is accusing Turkey of helping jihadists recruit fighters from the Caucasus and Central Asia to fight in Syria, according to a letter sent to the U.N. Security Council.

Russian Ambassador Vitaly Churkin said in the letter dated February 10 that recruiters from the Islamic State group had reportedly established a network in the Turkish city of Antalya for foreign fighters from the former Soviet Union.

Saudi forces participating in any U.S.-led ground operation in Syria would focus on fighting the Islamic State group not President Bashar Assad, Saudi Arabia's foreign minister told AFP on Thursday.

In an interview in Riyadh, Adel al-Jubeir also said separate Saudi-led military operations in Yemen would continue until the country's government is fully restored to power and that the kingdom would not cut oil production despite falling prices.

Morocco said Thursday it had dismantled a "terrorist cell" of 10 people including a Frenchman suspected of having links to the Islamic State group and planning attacks in the country.

Authorities carried out the arrests in several towns including Essaouira, Meknes, Sidi Kassem and al-Jadida, an interior ministry statement said, without revealing the identity of those detained.