With the West still refusing to arm Syria's opposition in the bloody fight against the regime, rebels in the flashpoint northern city of Aleppo warn that they could turn to Al-Qaeda for help.

"We don't want Al-Qaeda here, but if nobody else helps us, we will make an alliance with them," said Abu Ammar, a rebel commander in the central Bab al-Nasr district of Aleppo, scene of raging battles for almost a month.

"And you can bet if Al-Qaeda comes here, they will brainwash the people," he said. "If Al-Qaeda enters Aleppo, the city will become their base within three months."

Syria's opposition has frequently called on a divided and deadlocked international community to act to halt President Bashar al-Assad's campaign of repression against a peaceful uprising that is now an armed insurgency.

It is pushing for the establishment of a no-fly zone similar to the one the United Nations authorised for Libya last year, or the channelling of weapons to the poorly equipped rebel Free Syrian Army.

But the FSA remains massively outweighed by the regular army.

"May God help us because it is impossible to defeat this regime," said Abu Ammar. "They have chemical weapons they will possibly use. They have tanks, planes, mortars, rockets and we have nothing."

He pleaded: "We want them to give us weapons to defend ourselves or to intervene militarily. We are angry. The Syrian people still like the European countries, but if it continues like this, you end up hating them."

Experts have repeatedly warned that the uprising could take on an increasingly radical flavour, if calls for assistance went unheeded.

In recent months, reports of foreign jihadists flocking to Syria via its porous border with Turkey have raised alarm, although fighters and analysts say there is no big Al-Qaeda presence yet.

However, a State Department report last month said the Iraqi branch was believed to be extending its reach into Syria to try to exploit the uprising.

The number of Al-Qaeda fighters in Syria was believed to be small, State Department coordinator for counterterrorism, Daniel Benjamin, said.

"But there is a larger group of foreign fighters, many of whom are not directly affiliated with AQ, who are either in or headed to Syria. And clearly, this is a matter of concern for all who fear greater violence in Syria and for regional stability."

An AFP journalist in Aleppo said last month he saw foreign fighters who claimed to hail from countries as varied as Algeria, Chechnya, France and Sweden come to join Syrian rebel group, the Tawhid Brigade.

Another reporter said he saw fighters from a number of Arab countries including Saudi Arabia at a border crossing between Turkey and northern Syria.

"Why doesn't the government of your country do anything to help us?" Abu Ahmed, a fighter with the Martyrs of Atareb Battalion in the rebel-held Aleppo district of Sukari, pleaded with an AFP photographer.

"In Libya, they helped get rid of (now slain dictator Moamer) Kadhafi, but here in Syria they leave us to die."

Analysts said there were already several splinter groups on the ground who employ the same methods as Al-Qaeda.

Fears of Iraq-style violence multiplied in May when twin suicide bombings in Damascus killed at least 55 people and wounded several hundred -- the deadliest attacks since the uprising erupted in March 2011.

Al-Nusra Front, an Islamist group unknown before the revolt, claimed responsibility for the bombings as well as previous attacks in Damascus and Aleppo.

-- "Neither the Arabs nor the West" --

Washington, which has long accused Damascus of turning a blind eye to extremists crossing through into Iraq, has refused to supply arms to the rebels, lest they fall into the hands of Al-Qaeda.

In February, when Qaeda leader Ayman al-Zawahiri openly expressed support for the Syrian revolt, rebel groups rejected his statement as "interference."

From the start of the uprising, Assad's regime has claimed to be fighting a foreign-planted, Islamist insurgency led by "armed terrorist groups."

Though activists have frequently mocked the regime's discourse, they also sense the emergence of radical groups whose agenda is not freedom and democracy, but the establishment of an Islamic state.

The majority of Syria's population is Sunni Muslim, but the country is led by the Alawite Assad clan. Members of the Alawite community -- an offshoot of Shiite Islam -- are considered by radical Islamists as apostates.

Though many rebels may not share this view, there are growing signs that they may be willing to make a pact with even the most radical groups to bring Assad down.

"The main aim is to stop this bloodshed in Aleppo. If neither the West nor the Arabs will help us, we will ask for the help of Al-Qaeda to stop the bloodshed," said Baraa, an anti-regime activist in Aleppo, who said Al-Qaeda's possible presence would not mean that they would take over.

"In the end, the people of Aleppo will decide their fate," Baraa said via Skype.

"The people who have stood against and fought a dictator like Bashar al-Assad... I am sure that the same people can also fight Al-Qaeda."