The "extremely dangerous" conflict in Syria could have global repercussions, says UN Secretary General Ban Ki-moon, as fresh violence erupted and an al-Qaeda-inspired group claimed responsibility for two suicide bombings in Damascus.

The uprising that began a year ago has transformed into an armed insurgency that many fear is pushing the country toward civil war.

Because of Syria's close alliances with Iran and the Lebanese militant group Hezbollah, there are deep concerns that the violence could spread beyond the country's borders, especially if other nations arm the rebels or send in their own troops.

During a UN Security Council committee meeting Wednesday, the United States, Britain, and France accused Iran of smuggling weapons to Syria to help put down the uprising.

Syrian army soldiers look through a hole in a building as they search for Syrian rebels in a suburb of Damascus, Syria, on Tuesday. (Associated Press)

"We do not know how events will unfold," Ban said during a speech in the Indonesian capital, Jakarta. "But we do know that we all have a responsibility to work for a resolution of this profound and extremely dangerous crisis … that has potentially massive repercussions for the region and the world."

His comments came as the previously divided UN Security Council united to approve a non-binding statement calling on the Syrian government and opposition to immediately implement proposals by international envoy Kofi Annan to end the bloodshed.

Syrian activists reported shelling by government forces in hotspots including the central province of Homs, and fighting between army defectors and soldiers in Damascus suburbs.

Large-scale bombings near government security buildings in the capital, Damascus, and the northern city of Aleppo have added a new and increasingly deadly element to the revolt.

Al Qaeda linked to bombings

U.S. intelligence officials have pointed to al-Qaeda in Iraq as the likely culprit, raising the possibility its fighters are infiltrating across the border to take advantage of the turmoil.

In a statement posted Wednesday on a militant website, an Islamist group called the Al-Nusra Front to Protect the Levant claimed responsibility for twin suicide bombings in Damascus on Saturday. The blasts, which targeted the air force intelligence building and the criminal security department, killed at least 27 people, the state-run news agency said.

"It's looking more and more like Al-Nusra is just a front for AQI in Syria," a U.S. official said Wednesday, speaking on condition of anonymity to discuss matters of intelligence.

The Associated Press could not verify the authenticity of Wednesday's Al-Nusra statement, which said the attacks were in retaliation for the Syrian regime's shelling of residential areas in opposition strongholds in Homs, Idlib, Hama and Daraa.

"We tell the [Syrian] regime to stop the massacres against the Sunnis, otherwise, you will bear the sin of the Alawites," the Al-Nusra Front said. "What is coming is more bitter and painful, with God's will."

Al-Qaeda supporters are largely Sunni Muslim extremists. Syria's military and political leadership is stacked heavily with members of the minority Alawite sect, an offshoot of Shia Islam to which Assad and the ruling elite belong.

The group also has claimed responsibility for earlier suicide attacks.

Sunnis make up the majority of Syria's 22 million people, as well as the backbone of the opposition. Al-Qaeda's involvement could further fuel sectarian tensions unleashed by the uprising.

Syrian deaths estimated at 8,000

The UN estimates that more than 8,000 people have been killed since the uprising began last March.

The Syrian revolt started with mostly peaceful protests against the government, inspired by the Arab Spring uprisings across the region. But the regime cracked down violently, opening fire on demonstrations and rounding up thousands of protesters. Assad has justified the crackdown by saying terrorists and foreign extremists are driving the revolt.

The opposition denies that, saying some army defectors and others have been forced to take up arms because of the ferocious crackdown.

In this citizen journalism image taken Tuesday, provided by the Local Coordination Committees in Syria and accessed on Wednesday, Syrian rebels step on a portrait of Syrian President Bashar Assad in Idlib province, Syria. (Local Coordination Committees in Syria/Associated Press)

The non-binding statement approved by the 15 Security Council members spells out Annan's proposals, which include a ceasefire first by the Syrian government, a daily two-hour halt to fighting to evacuate the injured to safety and provide humanitarian aid, and inclusive Syrian-led political talks "to address the legitimate concerns of the Syrian people."

In a bid to win support from Russia and China, which have twice vetoed European and U.S.-backed resolutions condemning Assad's crackdown, France watered down the statement to eliminate possible consideration of "further measures" that could include sanctions or military action.

Instead, the presidential statement now asks Annan to update the council regularly on the progress of his mission and says that "in the light of these reports, the Security Council will consider further steps as appropriate."

A presidential statement, which needs approval from all council members, becomes part of the council's permanent record. It is stronger than a press statement, which does not. But unlike resolutions, neither statement is legally binding.

U.S. Secretary of State Hillary Rodham Clinton commended the council's unanimous support.

"The council has now spoken with one voice," said Clinton, who had lambasted Russia and China for vetoing two tougher UN resolutions on Syria in recent months.