European and Arab foreign ministers are meeting at the Arab League headquarters in Cairo, Egypt, to discuss the Syrian crisis.
Catherine Ashton, the EU foreign policy chief, who addressed Tuesday's opening session, welcomed the creation of a new opposition bloc, but warned of a spillover of the conflict.
The Syrian National Coalition was formed over the weekend in the Qatari capital, Doha, in a bid to unite the divided opposition to the Syrian regime.
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"I want to welcome the work done in Doha to build and bring together the opposition, to be inclusive of the people in Syria to be determined in the offer they make to the people," Ashton told delegates.
"But the tragedy of Syria is a tragedy that affects not just that country but the whole region."
"Countries represented here know the challenges of refugees fleeing for their lives, the threat of the overspill of violence," she said.
The Arab League on Monday recognised the National Council as "the legitimate representative and main interlocutor with the Arab League" and called on other dissidents to join the coalition.
"It is the legitimate representative of the Syrian opposition," Qatari Prime Minister Hamad bin Jassim Al Thani, who heads the Arab League group for Syria, told reporters.
The Gulf Co-operation Council has gone further than the Arab League, saying on Monday its six member states had decided to recognise the National Coalition as the legitimate representative of the Syrian people.
Laurent Fabius, the French foreign minister, said on Tuesday on the sidelines of the talks in Cairo that France will support the new block.
"Now they are united, it's very important... France will support them," Fabius told reporters.
The council is headed by moderate Muslim cleric Ahmad Mouaz al-Khatib.
Fabius met both Khatib and George Sabra, the head of the Syrian National Council, a powerful opposition grouping which finally agreed to join the wider, more representative bloc.
The mainly exiled Syrian National Council had been accused of being out of touch with the Syrians fighting on the ground against the regime of President Bashar al-Assad.
The opposition says more than 35,000 people have been killed in the conflict. Hundreds of thousands have fled across the borders to neighbouring countries and an estimated one million people have been displaced inside Syria.