European Union foreign ministers have said they view Syria's just-formed National Coalition to be the "legitimate representatives" of the Syrian people.
A statement from the bloc's 27 ministers on Monday welcomed the November 11 formation of the National Coalition for Syrian Revolutionary and Opposition Forces and said: "The EU considers them legitimate representatives of the aspirations of the Syrian people."
"This agreement represents a major step towards the necessary unity of the Syrian opposition."
The National Coalition, headed by Ahmad Mouaz al-Khatib, will take Cairo as its headquarters.
France, which last week became the first Western country to recognise the Coalition as sole representative of the Syrian people, had urged fellow EU nations to follow in its footsteps.
Monday's statement is a step short of the French stance.
Italy, however, joined France on Monday and Britain is expected to clarify its position in a parliamentary debate on Tuesday.
The group was formed in Qatar after 20 months of conflict that activists say has killed more than 39,000 people.
'Sympathy vis-a-vis coalition'
For his part, Laurent Fabius, French foreign minister, said that all his EU counterparts had expressed "much sympathy vis-a-vis the coalition".
"I think we will invite the Coalition leaders to our next meeting [in December] to allow them to talk to all of the foreign ministers, which will be highly symbolic," he said.
In-depth coverage of escalating violence across Syria
The EU ministers' statement urged the National Coalition to continue "to work for full inclusiveness" while respecting human rights and democracy and engaging with all opposition groups and sections of Syrian society.
"The EU stands ready to support this new Coalition in these endeavours and is relations with the international community," it said.
William Hague, British foreign secretary, who has said he needed to know more about the new opposition before offering full recognition, said he had had "a good meeting" with the new Syrian opposition on Friday in London.
He planned to speak to the British parliament later this week on how to increase support for the coalition.
"I was impressed with their objectives, with their clarity, with the breadth of their support, their determination to be inclusive in Syria of all communities and groups within Syria," Hague said on the sidelines of the Brussels meeting.
Rebels seize army base
The latest diplomatic development took place as clashes raged in different parts of Syria.
Also on Monday, Syrian rebels said they had seized the headquarters of an army battalion near the southern gate of Damascus, the nearest military base to the capital reported to have fallen to opposition fighters.
Two units of the rebel groups Ansar al-Islam and Jund Allah Brigades said in a statement that they had taken the base of the Air Defence Battalion near Hajar al-Aswad after four days of fighting.
Video footage showed rebels walking through the site, past destroyed anti-aircraft guns, and one commander saying on a walkie-talkie: "We have completely seized the compound."
Independent verification of the report was not possible.
Opposition activists said the Syrian army had attacked southern districts of Damascus with shelling and rockets all day to try to stop the rebels seizing the base, in some of the heaviest bombardment on the capital in the 20-month revolt.