A coalition of more than 70 partners, including the U.S., pledged Sunday to send millions of dollars and communications equipment to Syria's opposition groups, signalling deeper involvement in the conflict amid a growing belief that diplomacy and sanctions alone cannot end the Damascus regime's repression.

The shift by the U.S. and its Western and Arab allies toward seeking to sway the military balance in Syria carries regional risks because the crisis there increasingly resembles a proxy conflict that could exacerbate sectarian tensions. The Syrian rebels are overmatched by heavily armed regime forces.

The summit meeting of the "Friends of the Syrian People" follows a year of failed diplomacy that seems close to running its course with a troubled peace plan led by UN-Arab League envoy Kofi Annan.

Turkish PM Recep Tayyip Erdogan, right, told Sunday's session of the Friends of the Syrian People conference in Istanbul that military options should remain on the table for stemming the violence in Syria. (Bulent Kilic/AFP/Getty)

Indeed, U.S. Secretary of State Hillary Rodham Clinton and other participants at the conference in Istanbul uniformly expressed concern that Annan's plan might backfire, speculating that Syrian President Bashar Assad would try to manipulate it to prolong his hold on power.

Clinton said she was waiting for Annan's report to the UN Security Council on Monday on the status of his peace plan.

"There cannot be process for the sake of process. There has to be a timeline. If Assad continues as he has, to fail to end the violence, to institute a cease-fire, to withdraw his troops from the areas he has been battering … then it's unlikely he is going to ever agree," she said. "Because it is a clear signal that he wants to wait to see if he has totally suppressed the opposition. I think he would be mistaken to believe that. My reading is that the opposition is gaining in intensity, not losing."

Clinton said the United States is providing communications equipment to help anti-government activists in Syria organize, remain in contact with the outside world and evade regime attacks.

Agreed to UN plan

The Syrian regime agreed last week to Annan's plan, which calls for an immediate cease-fire, humanitarian access to besiegedcivilians and a political negotiation process led by Syrians. Since then, there have been daily reports of violence, including shelling Sunday in the central city of Homs that activists said killed more than two dozen people.

The uprising began in March 2011 as part of the Arab Spring with peaceful protests calling for political reforms. Assad's regime sent tanks, snipers and thugs to try to quash the revolt, and many in the opposition have taken up arms to defend themselves and attack government troops. The United Nations says more than 9,000 have died.

Conference participants in Istanbul said Saudi Arabia and other Gulf countries are creating a fund to pay members of the rebel Free Syrian Army and soldiers who defect from the regime and join opposition ranks. One delegate described the fund as a "pot of gold" to undermine Assad's army.

Participants confirmed the Gulf plan on condition of anonymity because details were still being worked out. One said the fund would involve several million dollars a month. It is said to be earmarkedfor salaries, but it was not clear whether there would be any effort to prevent the diversion of money to weapons purchases, a sensitive issue that could prompt stronger accusations of military meddling by foreign powers.

The delivery of humanitarian aid to Syria's beleaguered civilians is a key provision of Annan's plan. Clinton announced $12 million US in additional aid for Syria's people — doubling the total U.S. assistance so far.

The Saudis and other Arab Gulf states have proposed giving weapons to the rebels, while the U.S. and other allies have balked out of fear of fueling an all-out civil war. Washington hasn't taken any public position on the fund, but it appears that it has given tacit support to its Arab allies.

Mohammed al-Said, a Syrian activist in the town of Duma, northwest of Damascus, said salaries might encourage further defections, but that only arms would turn the tide against Assad.

"What is clear to us is that only fighting can make this regime leave," he said via Skype, adding the opposition wanted arms more than military intervention so they could topple Assad themselves.

Fayez Amru, a rebel who recently defected from the military and is now based in Turkey, welcomed the decision as a "humanitarian step in the right direction" but also said weapons were needed.

"We feel let down by the international community. I don't know why there is hesitation by the West … maybe this will help at least keep the rebels on their feet," Amru said.

International conspiracy

In Damascus, Syria blasted the conference, calling it part of an international conspiracy to kill Syrians and weaken the country. A front-page editorial in the official Al-Baath newspaper said the meeting was a "regional and international scramble to search for ways to kill more Syrians, sabotage their society and state, and move toward the broad objective of weakening Syria."

Delegates to the Istanbul meeting talked of tighter sanctions and increased diplomatic pressure on Assad, and Syrian opposition representatives promised to offer a democratic alternative to his regime. Yet the show of solidarity at the conference was marred by the absence of China, Russia and Iran.

Turkish Prime Minister Recep Tayyip Erdogan said military options might have to be considered if Syria does not co-operate with Annan's plan and the UN Security Council does not unite against Assad.

"If the UN Security Council fails once again to bring about its historic responsibility, there will be no other choice than to support the Syrian people's right to self-defence," Erdogan said.

Burhan Ghalioun, leader of the opposition Syrian National Council, called for the strengthening of Syrian rebel forces as well as "security corridors" in Syria, a reference to internationally protected zones on Syrian territory that would allow the delivery of aid to civilians. However, the nations meeting in Istanbul failed to agree on such an intervention, which could involve the deployment of foreign security forces.