In a key foreign policy address yesterday, barely four weeks before the US presidential election, Romney accused incumbent Barack Obama of weak leadership in the Syrian crisis which he said was emblematic of

an administration that opts to "lead from behind".

"In Syria, I will work with our partners to identify and organise those members of the opposition who share our values and ensure they obtain the arms they need to defeat Assad's tanks, helicopters, and fighter jets," the Republican candidate pledged.

Obama, worried that shoulder-fired missiles and other advanced weapons could end up in the hands of terrorists, has not provided arms for the rebel groups, although he has arranged for the delivery of communications equipment.

UN chief Ban Ki-moon called earlier yesterday for a halt to foreign arming of either side.

"I am deeply concerned by the continued flow of arms to both the Syrian government and opposition forces. I urge again those countries providing arms to stop doing so,"

Ban said.

The Syrian government accuses Turkey and Gulf states Qatar and Saudi Arabia of backing the rebels.

The opposition charges that Assad's regime is receiving support from his close ally Iran.

The head of the opposition Syrian National Council held talks with

rebel commanders in the town of Bab al-Hawa, just across the border from Turkey, rebel sources said.

Sayda has been attempting to broaden the base of the exiled opposition bloc but only to those groups that back the armed rebellion against Assad's rule.

His crossing into rebel-held territory came with tensions still running high after the shelling of a Turkish border village last week killed five civilians, including a mother and her three children.