CAIRO: EU foreign ministers meeting in Cairo on Tuesday welcomed a newly formed Syrian opposition bloc, urging it to bring in more regime dissenters, as the coalition chief appealed for weapons.

After four days of talks in the Qatari capital Doha, Syrian opposition groups agreed on Sunday to unite under the banner of the National Coalition headed by moderate Muslim cleric Ahmed Moaz al-Khatib.

Khatib called on world powers to arm rebels, telling AFP they desperately needed arms if they were to "cut short the suffering of the Syrians and their bloodshed."

"We need specialised weapons," he added, without elaborating.

The conflict in Syria has killed more than 37,000 since it broke out in March 2011, according to the Syrian Observatory for Human Rights.

French Foreign Minister Laurent Fabius, who was in Cairo for talks between European Union and Arab League ministers, urged the international community to recognise the body.

"Our hope is that the different countries recognise the Syrian national coalition as the legitimate representative of the Syrian people... France's role is to make that hope possible," Fabius told reporters in Cairo.

"The opposition has taken a huge step forward," said Fabius, who met earlier with both Khatib and George Sabra, head of the Syrian National Council, the main opposition group that finally agreed to join the wider, more representative bloc.

"It is a very important milestone and a very big step towards (recognition)," British Foreign Secretary William Hague told reporters.

"We do now want to see the details of the agreement made in Doha implemented, and we want to see in practice that the Syrian opposition or the coalition now being assembled is as inclusive as possible of opposition groups and all communities in Syria," said Hague.

"We want to see that they have support inside Syria. That is a very crucial consideration. If they do all these things, well then, yes, we will be able to recognise them as the legitimate representative of the Syrian people."

Khatib said his organisation was representative of most opposition groups, even as European countries and the Arab League fell short of recognising it as a government in exile.

"Many groups have joined. Some have reservations, and we are in touch with everyone. The vast majority has joined. It is the strongest coalition and represents Syria internally," he said in a telephone interview in Cairo.

The call for arms is something some European countries are willing to look into.

"We have an EU embargo on the whole of Syria. We are not excluding any options for the future because this desperately serious crisis is getting worse and worse all the time. But our approach has been to give non-lethal support to the opposition, that is how it stands today," Hague said.

Fabius said the coalition had presented things "in a new light" by saying "they need arms to defend themselves from attacks by Bashar al-Assad, particularly air strikes. It is something we will consider," Fabius said.

Ashton, who addressed ministers at the Arab League, welcomed the Doha agreement but warned of a spillover of the conflict.

"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," she said. "Countries represented here know the challenges of refugees... the threat of the overspill of violence."

The 22-member Arab League on Monday recognised the National Coalition as "the legitimate representative of the Syrian opposition".

The Gulf Cooperation Council has gone further than the Arab League, saying on Monday its six member states had decided to recognise the coalition as "the legitimate representative of the Syrian people".