While rebels have received military support from Assad's foreign enemies, states including Saudi Arabia, Turkey and Qatar and the United States, their calls for more effective weapons including anti-aircraft missiles have gone unanswered.
On Wednesday, senior opposition official, Riyad Hijab, announced the names of opposition negotiators saying their chief will be Mohammad Alloush, a representative of an Islamic rebel group.
Meanwhile Russia wants Kurdish PYD co-chair Saleh Muslim and Syrian former deputy prime minister and opposition MP Qadri Jamil at the table.
Air strikes also hit areas in the east near where government forces have been fighting against Islamic State, which controls most of the province.
U.S. Secretary of State John Kerry is dismissing posturing from the Syrian government and opposition ahead of U.N.-led peace talks that are supposed to begin this week.
The Geneva talks were scheduled to open on January 25, but diplomats have said they could be delayed if the question of the opposition delegation is not resolved.
Syria's conflict first erupted with anti-government protests in 2011 but has since morphed into a bloody, complicated war that has killed more than 260,000 people.
The statement issued Saturday was signed by the Syrian National Coalition, the main Western-backed opposition group, as well as 44 rebel groups including Jaish al-Islam.
"Ever since President Assad was flown in to be received by our president previous year, his attitude has been less that satisfactory, and this does interfere with our efforts towards a political solution", the Russian authority on Syria who is involved in Moscow's diplomacy said.
It added that dozens of people were wounded and the toll was expected to rise.
Ruling Ba'ath Party assistant secretary Hilal al-Hilal said: "We are not going to give today what we did not give over the past five years".
The LCC and Abu Leila said the air raids w ere carried out by Russian warplanes but it was not possible to independently confirm the claim.
