Syria's longtime vice president said Sunday that his regime and the rebels are both going down a losing path after 21 months of civil war, a rare admission by a top government official that President Bashar Assad's victory is unlikely.

The comments by Farouk al-Sharaa came as an Islamist faction of Syrian rebels captured an infantry base in the northern city of Aleppo, and Syrian warplanes blasted a Palestinian refugee camp in Damascus, killing eight people and wounding dozens, activists said.

Syrian Vice-President Farouk Al-Sharaa said in an interview with Lebanese newspaper Al-Akhbar neither the rebels nor the Assad regime can "decide the battle militarily." (Bassem Tellawi/Associated Press)

Al-Sharaa told the Lebanese newspaper Al-Akhbar that neither the rebels nor the Assad regime can "decide the battle militarily." It appeared to be an attempt to show that the rebels are not the solution to the Syria conflict, and their victory might bring chaos to the country.

Balancing that, he said the Assad regime "cannot achieve change."

The solution to the conflict must come from within Syria, al-Sharaa said, adding that any political settlement "must include stopping all types of violence, and the creation of a national unity government with wide powers."

The Assad regime has long rejected Western involvement in the civil war and has called for talks with the opposition. Most rebel groups refuse to meet with Assad, demanding his removal from power before laying down their arms.

Excerpts of the interview were posted on Al-Akhbar's English-language website late Sunday. The full interview will be published on Monday, the newspaper said.

Iranian peace plan for Syria

Al-Sharaa's comments coincided with a step-by-step peace plan for Syria outlined by Iranian officials on Sunday. It would be capped by Syrian elections that presumably could usher in a new leader in Damascus.

Tehran is Assad's closest and perhaps only remaining regional ally and the initiative suggests its embrace of the Syrian president could be cooling.

The initiative — while almost certain to be rejected by Syrian rebel factions — marks one of the clearest signals yet that Iran's leadership is looking to hedge its bets and remain a player in Syrian affairs if Assad is toppled. It was unclear whether al-Sharaa's comments were timed to co-ordinate with the Iranian initiative.

Al-Sharaa, 73, a longtime loyalist to the Assad family, has been a controversial figure since the start of the uprising.

He appeared in public in late August for the first time in weeks, ending repeated rumours that he had defected. The regime has suffered a string of prominent defections in recent months, though Assad's inner circle and military have largely kept their cohesive stance behind him.

Assad and his inner circle are predominantly Alawites, a minority sect that is an offshoot of Shiite Islam. The opposition is dominated by the majority Sunni Muslims.

Rebels take infantry base in Aleppo

Early on in the uprising, the Syrian president delegated to al-Sharaa, a skilled diplomat, responsibility for holding a dialogue with the opposition. A Sunni from the southern town of Daraa, birthplace of the Syrian uprising, al-Sharaa's silence since the start of the uprising made him a prime candidate for rumours that he broke with the regime.

His comments after a long silence suggest he may be have been given a green light to sound out readiness for a political settlement.

Syrian rebels have made significant tactical advances in the past weeks, capturing air bases and military installations near Syria's largest city of Aleppo and in the capital Damascus. On Sunday, an Islamist faction took an infantry base in Aleppo, a second army base that was captured from the troops in the northern city in a week.

'Every day that passes, the military and political solution gets more elusive.'— Farouk al-Sharaa, Syrian vice-president

Also, Western nations are talking of stepped up aid to the rebels. And there were mixed messages last week from Assad's key international ally Russia, which tried to backpedal after a top diplomat said Assad is losing control of his country.

Al-Sharaa offered an unusually bleak public assessment of the civil war.

"Every day that passes, the military and political solution gets more elusive," he said. "We need to be in a position to defend Syria. We are not in a battle for an individual or a regime."

The uprising started in March 2011 as peaceful protests but quickly turned into a civil war after the government's brutal crackdown on dissent. Activists say more than 40,000 people have been killed.