Syrian Health Minister Halki is sworn in as the new prime minister by Syrian President Assad in Damascus (Reuters)

Russian Deputy Foreign Minister Mikhail Bogdanov has said that embattled Syria's president Bashar al-Assad has agreed to step down.

Speaking to Saudi paper Al-Wattan, Bogdanov said that what is needed is a peaceful transition of powers.

The Russian diplomat revealed that Maher Assad, the president's brother, was severely injured in the Damascus blast at the National Security HQ that killed four close aides of Assad

Maher Assad, commander of Syria's 4th Division and of the Republican Guards, lost both his legs in the explosion and is struggling for life, Bogdanov said.

The four senior officials killed were Syrian general Hassan Turkman, head of President Bashar al-Assad's military crisis unit, Hafez Makhlouf, head of investigations at the Syrian Intelligence Agency, Defence minister Daoud Rajiha and Assad's brother-in-law Assef Shawkat.

"Putting down the weapons is the best solution to prevent Syria from deteriorating into civil war, which we believe is imminent," Bogdanov told Al-Watan in a phone conversation quoted by the Times of Israel. "We [Russia] are the only ones who believe in a drive toward a political solution."