BRUSSELS (Reuters) - European Union governments on Friday rejected Franco-British efforts to lift an EU arms embargo to allow weapons supplies to Syrian rebels, saying this could spark an arms race and worsen regional instability.

Members of the Free Syrian Army walk with their weapons in Bab Amro in the city of Homs, in a picture provided by Shaam News Network March 11, 2013. REUTERS/Basel Fouad /Shaam News Network/Handout

France and Britain found little support for their proposal at an EU summit in Brussels, diplomats said, but EU foreign ministers will consider the issue again next week.

French President Francois Hollande, backed by British Prime Minister David Cameron, pressed for the embargo to be lifted, saying Europe could not allow the Syrian people to be massacred.

Western nations mostly have stood on the sidelines as 70,000 Syrians have been killed, according to a U.N. estimate, during a two-year-old revolt against Syrian President Bashar al-Assad.

German Chancellor Angela Merkel, a leading opponent of lifting the arms embargo, said there was a danger that Assad’s allies Russia and Iran could step up arms supplies to his government if the 27-nation EU lifted its restrictions.

Just because Britain and France now wanted to drop the ban, that didn’t mean 25 other states must follow suit, she told a news conference in Brussels. “That will not be the case.”

“Others have, with, in my view, very good reasons ... pointed to the fact that Iran and also Russia are only waiting for a signal to export arms (and) that one must also be aware of the fragile situation in Lebanon and what that means for the arming of Hezbollah,” she said.

German officials cite what happened in North Africa where guns smuggled out of Libya helped arm Islamists in Mali.

European Council President Herman van Rompuy said leaders had asked their foreign ministers to look at the arms embargo “as a matter of priority” at a March 22-23 meeting in Dublin.

GUARANTEES

Hollande said he had received guarantees from the Syrian opposition that any arms delivered to them would end up in the right hands.

“I will do everything so that at the end of May at the very latest ... a common solution is adopted by the Union,” he said.

Syrian insurgents are a disparate array of mostly locally organized units, only some of which are loyal to the Free Syrian Army, which is loosely linked to the internationally recognized political opposition, the Cairo-based Syrian National Coalition.

Others are hardline Sunni Islamist factions, such as the al Qaeda-linked Nusra Front, which Washington calls a terrorist group, but which has won prestige for its battlefield exploits.

French officials say that, for now, Paris is keener to use the scrapping of the embargo as a bargaining chip to put political pressure on Assad than to actually supply arms. Britain, too. has not said it would arm the rebels.

France and Britain reopened the Syrian issue only days after EU states had hammered out a hard-fought compromise to relax the embargo to allow non-lethal aid to the opposition, such as armored vehicles and technical assistance.

A French foreign ministry official said any changes to the arms embargo would be gradual and would likely be implemented only when the current package of EU sanctions on Syria expires at the end of May.

“It is not going to take effect immediately. It will probably take a few weeks to try to agree and probably be effective at the end of May,” Justin Vaisse said during the General Marshall Fund’s annual Brussels Forum.

Cameron said pressure must be applied to bring about a transition in Syria.

“As things stand today, I am not saying that Britain would actually like to supply arms to rebel groups,” he said.

“What we want to do is work with them and try to make sure that they are doing the right thing. And with technical assistance we are able to do that.”

The arms ban is part of a package of EU sanctions on Syria that rolls over every three months. An extension agreed last month expires on June 1. Without unanimous agreement to renew or amend it, the embargo lapses, along with the sanctions.

Although an EU agreement to lift the embargo completely is unlikely, there could be scope for a compromise, perhaps expanding the aid that EU governments may give to the rebels.

France and Britain have both suggested they could act alone if no EU-wide agreement can be reached.

“Two countries may want this, but the overwhelming majority don’t and to lift the embargo there’s got to be unanimity,” one senior EU official said. “It’s not just Germany that has concerns, but Sweden, Spain, Austria and others too.”