Shells slammed into the central Syrian city of Homs yesterday, killing more than two dozen people, activists said.
The latest deaths came as Syria's government defied ceasefire demands and international efforts to boost the rebels.
Activists said heavy machine gun fire and artillery pounded the districts of Khaldiyeh, Bayada and Safsafa in the battered city, despite world demands on the Syrian regime to end violence that has killed thousands of people in the past year.
In the latest steps, participants at the "Friends of the Syrian People" meeting in Istanbul said Saudi Arabia and other Gulf countries are creating a multimillion-dollar fund to pay members of the rebel Free Syrian Army and soldiers who defect from the regime.
One delegate described the fund as a "pot of gold" to undermine President Bashar Assad's army.
US Secretary of State Hillary Clinton said Washington is providing communications equipment to help opposition members in Syria organise, remain in contact with the outside world and evade attacks.
The Syrian government blasted the meeting, calling it the "Enemies of Syria" gathering.
Damascus has consistently dismissed the country's year-long uprising as a foreign-engineered plot.
Syria's uprising began in March last year with peaceful protests calling for political reforms. Dissent spread as Mr Assad's forces deployed tanks, snipers and thugs to quash it, and many in the opposition have taken up arms since.
The United Nations says more than 9,000 people have been killed.
Former UN Secretary General Kofi Annan is pushing to end the violence with a six-point plan that calls on the government to immediately pull its forces out of cities and towns and abide by a two-hour halt in fighting every day to allow humanitarian access and medical evacuations, while arranging a permanent ceasefire. Syria has said it agrees to the plan but has rejected what it actually requires Damascus to do.
Foreign ministry spokesman Jihad Makdessi said Syria would not withdraw its forces from towns and cities before life returns to normal there.
Leaders of Syria's scattered opposition have also rejected dialogue with the Assad regime, accusing it of stalling for time and saying it has killed too many people to be considered serious about peace.
Activists said violence continued inside the country and criticised the Istanbul meeting as a waste of time.
"The conference has to arm the opposition, the Free Army. That is the best thing they can do because we're tired of promises and initiatives," said activist Hadi al-Yousef.
The British-based Syrian Observatory for Human Rights said at least 36 people were killed in military operations across the country yesterday, most of them civilians. They included four government soldiers killed in an attack on their convoy in the Idlib province.
The Local Co-ordination Committees put the number of deaths at 50, saying 18 died in Homs province.