2014 marked Syria's deadliest year yet

The list also includes members of the tolerated domestic opposition, including Hassan Abdel Aazim, Aref Dailia and Fateh Jamous.

Qadri Jamil, a former deputy prime minister who was sacked in 2013 and has good ties with Russia, was also invited.

It was not immediately clear whether any of the invitations had been accepted.

The SNC's general assembly is due to meet in Turkey for three days beginning Friday and is expected to discuss the invitations.

Russia, a key backer of Assad, has been trying to relaunch peace talks that would include meetings between delegates of the regime and the fractured opposition.

In December, the foreign ministry said Moscow planned to host opposition delegations in late January, possibly followed by a visit by regime representatives that could bring the two sides together for talks.

Bloodiest year yet

The war has become a multi-front conflict and contributed to the rise of extremist groups such as the Islamic State group (IS, formerly ISIS).

IS controls a swathe of territory in both Syria and neighbouring Iraq, where government figures showed at least 15,000 people were killed in 2014.

The Syrian Observatory for Human Rights, a monitoring group, recorded 76,021 deaths in Syria last year.

The UK-based group documented the deaths of nearly 18,000 civilians throughout 2014, among them 3,501 children.

The majority of the deaths were combatants, including nearly 17,000 jihadists, 15,747 rebel forces and 22,627 regime troops and militiamen, it said.

On Wednesday night, Assad visited troops and pro-regime forces in the east Damascus district of Jobar.

The president's official Facebook and Twitter accounts carried photographs of him in civilian clothes talking with two soldiers by a tank and shaking hands with a third.

"As the New Year begins, President Assad is in Jobar with the soldiers of the Syrian Arab Army," the caption said.

"If there is still a bit of joy in Syria, it is thanks to the victories you are winning against terrorism," Assad was quoted as telling them.

State television aired footage showing Assad sharing a meal with troops and being saluted by soldiers.

Jobar is a former rebel stronghold, but government forces have advanced steadily into it in past months.

It is strategic because of its proximity to Abbasid Square in Damascus, which is key to controlling the centre of the city.

It also provides access to the rebels' main rear base on the outskirts of the capital, Eastern Ghouta.

Syria's conflict has killed more than 200,000 people, displaced nearly half the country's population and spilled over into neighbouring countries.

The IS group that emerged from al-Qaeda's one-time Iraqi affiliate now controls a self-proclaimed Islamic "caliphate" in parts of Iraq and Syria.

Kidnapped aid workers

The fight against IS has drawn the United States back to Iraq, where it is training Iraqi forces and leading an international coalition to carry out air strikes against the group.

On Thursday, the Pentagon said coalition forces had carried out 17 strikes overnight in Syria, and 12 raids in Iraq.

Elsewhere, a video purporting to show two Italian aid workers kidnapped in northern Syria in August was posted online.

The footage showed two women dressed in black robes and headscarves identifying themselves as Vanessa Marzullo and Greta Ramelli.

The two, both in their twenties, were abducted at gunpoint by an unknown group in Aleppo province last year.

In the video, one of the women holds a piece of paper identifying the date as December 17, and the other urges the Italian government to win their release.

The video title on YouTube identifies them as hostages of al-Qaeda's Syrian affiliate al-Nusra Front.