Syria needs more time to end the conflict raging across the country, President Bashar al-Assad said in a television interview to be broadcast by pro-regime Al-Dunia channel on Wednesday.

Assad also scoffed at an idea being championed by Turkey of creating buffer zones within Syria to receive those displaced by the conflict, in advance excerpts of the interview screened by the private channel.

"I can summarise in one phrase: we are progressing, the situation on the ground is better but we have not yet won -- this will take more time," Assad said.

"Talk of buffer zones firstly is not on the table and secondly it is an unrealistic idea by hostile countries and the enemies of Syria," he added.

The Syrian leader also mocked those defecting from his regime, saying their departure amounted to a "self-cleansing of the government firstly and the country generally."

Al-Dunia said it would screen the full interview at 1800 GMT on Wednesday.

Assad's comments come a day after a car bomb rocked the funeral of two government loyalists in a Damascus suburb killing 27 people and as his army kept up its bombardment of rebel strongholds in the east of the capital.

Fighting between rebels and loyalist troops raged in several flashpoints, including in the commercial hub Aleppo, northwestern Idlib province and eastern Deir Ezzor.

Activists say around 25,000 people have been killed since the uprising against Assad's rule broke out in March last year, while the United Nations says more than 214,000 people have fled to neighbouring countries.