MOSCOW/ASTANA - The Russian Navy on Thursday fired seven cruise missiles at Islamic state targets in the suburbs of Syria’s Deir al-Zor, the Russian Defence Ministry said in a statement on Thursday.

It said the missiles were fired from two submarines in the eastern Mediterranean from a distance of 500-670 kilometres (727 miles).

“The targets were command posts, communication centres, as well as militants’ weapons and ammunition stockpiles in areas of south-east Deir al-Zor under the control of Islamic State,” the ministry said.

De-escalation zones deal

Russia, Turkey and Iran are close to finalising an agreement on creating four de-escalation zones in Syria, a senior Russian negotiator said on Thursday.

The three sides are discussing details of the agreement at meetings in Astana, the capital of Kazakhstan, Alexander Lavrentyev, who leads the Russian delegation, told reporters. Meanwhile, Separate suspected Russian and US-led coalition strikes on Syria's Deir Ezzor province killed at least 39 civilians on Thursday, the Syrian Observatory for Human Rights monitor said.

The strikes hit several parts of the eastern province, where parallel Russian and US-backed ground offensives are under way against the Islamic State group.

The Britain-based monitor said seven children were among the dead in the strikes, which hit multiple parts of the province including the city of Mayadeen, a remaining IS stronghold. The strikes come as Syria's army battles to oust IS from the provincial capital Deir Ezzor city, after breaking the jihadist group's two-year siege of government-held parts of the metropolis.

Backed by Russian air strikes, the army and allied fighters now hold over half the city, and are working to surround IS militants in the remaining parts.

On Thursday, the Observatory said the army seized the northern suburb of Al-Boghaliya, advancing to the adjacent western bank of the Euphrates river that slices diagonally across Deir Ezzor province.

They are still battling to take additional territory in the southern part of the city in order to encircle IS fighters.

On the opposite side of the river, the US-backed Syrian Democratic Forces, an alliance of Syrian Kurdish and Arab fighters, is also battling IS.

US-led and Russian strikes in support of the separate campaigns have killed dozens of civilians in recent days, including some fleeing the fighting and seeking shelter in tents along the banks of the Euphrates, according to the Observatory.

More than 330,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests before spiralling into a bloody civil war.

 Busloads of Islamic State fighters stranded in the Syrian desert reached militant-held territory after the US-led coalition stopped surveillance of the convoy, a monitor said on Wednesday.

Coalition drones had been circling the stranded 11-vehicle convoy for days and periodically picking off IS fighters if they strayed too far from the vehicles.

But the convoy, with as many as 200 militants and 200 civilians on board, arrived in Deir Ezzor eastern Syria "after the coalition decision to stop their surveillance on the convoy", said the Syrian Observatory for Human Rights, a Britain-based monitor.

A source on the ground told AFP "the operation is done, Daesh (IS) convoy reached Deir Ezzor province".

The US-led coalition on Friday pulled aircraft from the skies above the convoy so regime and Russian forces could go past, officials said.

"To ensure safe deconfliction of efforts to defeat ISIS, coalition surveillance aircraft departed the adjacent airspace at the request of Russian officials during their assault on Deir Ezzor," the coalition said in a statement.

The vehicles left the Lebanon-Syria border region on August 28 under an evacuation deal negotiated between IS and the powerful Lebanese Shiite movement Hezbollah, which has intervened in the war in neighbouring Syria to prop up the Damascus government.

But the US-led coalition pounded the road to Deir Ezzor with air strikes to prevent the convoy reaching the IS-held town of Albukamal on the Iraqi border.

The United States has repeatedly stressed that it was not party to the Hezbollah deal and said the fate of those aboard the buses was not a coalition issue.