MANAMA - Syria's new opposition coalition will announce the creation of a military council before a Friends of Syria meeting next week, to unify the ranks of insurgents, a top official said on Saturday.

National Coalition Secretary General Mustafa Sabbagh said the group "will announce the creation of a supreme military council before the Friends of Syria meeting in Marrakesh" due to take place on December 12.

In mid-November opposition factions met in Qatar and agreed to set up the National Coalition and bring together rebel forces under a supreme military council, as well as establish a judicial commission for rebel areas.

Under the deal the opposition agreed that the military council would take overall command of the various rebel groups on the ground to address US and other Western concerns over the growing influence of jihadist fighters.

The proliferation of jihadist fighters have stoked fears in the West with powers wary of providing weapons to rebels battling the regime of Syrian President Bashar al-Assad, lest the arms fall into the hands of extremists.

"The council will be exclusively responsible for receiving military aid which we obtain," from outside Syria, Sabbagh said.

He also stressed that the military command will not include radical groups such as Al-Nusra Front which, along with other Islamists rebels rejected the formation of the opposition National Coalition.

The Al-Nusra Front, which has become a formidable fighting force, has claimed the majority of suicide bombing attacks in Syria's 21-month-old insurgency that has cost tens of thousands of lives.

"Setting up the supreme military council is an important initiative to unify military action," said Sabbagh.

The council will comprise "commanders of the various military councils on the group and forces battling the regime, namely the (main rebel) Free Syrian Army," he said on the sidelines of a regional security forum in Bahrain.

Morocco has said it will host next Wednesday the fourth round of a Friends of Syria meeting of nations that support the opposition.

It will take place in the southern Moroccan city of Marrakesh, the foreign ministry has said, adding that more than 100 delegations will attend including members of the new Syrian opposition coalition.

Diplomatic sources in Rabat said US Secretary of State Hillary Clinton would be among those attending.

The meeting is aimed at finding "ways of ensuring a political transition, and of mobilising vital humanitarian aid," the foreign ministry in Morocco has said.

The group, which includes Western and Arab countries, last met in Paris in July.