Only "four or five" U.S.-trained rebels are fighting the Islamic State group in Syria, a top general said Wednesday during a grueling hearing about the progress of America's fight against the jihadist group.

After many of the first 54 graduates of a special training program were attacked in Syria by an al-Qaida affiliate in July, only a handful of rebels remain in the fight, General Lloyd Austin told the Senate Armed Services Committee.

The United Arab Emirates said on Wednesday it has spent "around $1.1 billion" helping Syrian refugees and on the fight against the Islamic State group.

The announcement follows criticism of rich Arab states for failing to take in Syrian refugees, as hundreds of thousands of people fleeing the conflict risk their lives to reach Europe.

Russia on Wednesday lambasted the U.S.-led coalition fighting Islamic State (IS) jihadists for achieving "very modest" results as Washington frets over an alleged military buildup by Moscow in Syria. 

The Kremlin -- one of President Bashar Assad's few remaining allies -- has been on a diplomatic drive to get the international coalition fighting IS in Iraq and Syria to coordinate with the regime in Damascus.

Russia's recent military build-up in Syria aims not only to boost the embattled regime of crucial ally Bashar Assad but also to send a strong signal to the West, experts say.

With President Vladimir Putin set to make Syria a key issue of his address to the U.N. General Assembly in New York later this month, Moscow is making it clear that it will not be ignored in the Middle East.

Hounded by both religious extremists and state officials at the Syrian university where they were teaching, Muhammad and Joury left on a journey helped by a British charity that has taken them to Scotland.

The husband and wife spent more than two years wandering across the Middle East, then to Turkey and finally to the University of Glasgow in Scotland, thanks to the Council For At Risk Academics (CARA).

The Kremlin denied a claim by a senior negotiator Wednesday that Russia had offered in 2012 to make Syrian President Bashar Assad step down in an "elegant way", saying it never called for regime change.

"I can only once more repeat that Russia is not involved in changing regimes. Suggesting that someone step aside -- elegantly or not -- is something Russia has never done," President Vladimir Putin's spokesman Dmitry Peskov told journalists, quoted by TASS state news agency.

Prime Minister Benjamin Netanyahu will travel to Russia next week for talks with President Vladimir Putin on Moscow's military support for the Damascus regime and "threats" facing Israel, his office said Wednesday.

Netanyahu will speak about "the deployment of Russian military forces in Syria," a statement said.

Archeological sites in Syria are being looted "on an industrial scale," with proceeds being used to fund Islamic State extremists, the head of UNESCO warned Wednesday.

"Satellite imagery shows that archeological sites in Syria are dotted by thousands of illegal excavations... that show there is looting on an industrial scale," Irina Bokova said in Sofia.

Syria's President Bashar Assad urged Syrian political and armed factions to unite in the fight against terrorist groups and said in comments aired Tuesday that there can be no political solution for the country's brutal civil war before terrorism is defeated.

Speaking in an interview with Russian media, he also blamed Europe for the refugee crisis currently hitting the continent, saying it is a direct result of the West's support of extremists in Syria over the past four years.

Around 1,000 refugees remained stranded Wednesday in the northwestern Turkish city of Edirne, near the Greek border, after being barred by Turkish authorities from continuing their journey to Europe.

"They cannot stay here. Maybe we will allow them to stay two or three days but then they have to leave," local governor Dursun Ali Sahin told Turkey's NTV channel, a day after police surrounded Edirne's bus station to contain the mostly Syrian crowd.