AMMAN/BEIRUT- Hundreds of Syrian rebel fighters and their families were preparing to leave Deraa city in southwest Syria on Sunday, to be taken on buses to opposition-held areas in the north, rebels told Reuters.

A rebel official, Abu Shaima, said at least 500 fighters were boarding around 15 buses and that he will be one of those leaving.

The fighters are leaving the Deraa al-Balad neighbourhood of Deraa city which had been under rebel control for years until a surrender deal last week. Under the deal, rebels would hand over weapons and fighters who do not wish to live under state rule would be transferred out.

The Syrian government, backed by the Russian military, has captured most of Deraa province in an offensive that began in June.

Deraa city was the scene of the first major peaceful protests against Syrian President Bashar al-Assad's authoritarian rule in March 2011 which spiralled into a war now estimated to have killed half a million people.

Abu Bayan, a rebel commander, said most rebels in Deraa have decided to stay put rather than face an uncertain future in the opposition-held north, in the hope Russian keeps to its promises to protect them against any retribution by Syrian authorities.

Fighter Abdullah Masalmah, who had chosen to leave and was about to board the bus, said: "I cannot forget the thousands of those who were killed by the regime let alone the orphans, wounded and the detainees. I don't trust the Russians or the regime."

Syrian state news agency SANA said on Sunday that rebels had been handing over their heavy weapons to the Syrian army, showing images of armoured vehicles and heavy artillery it said had been collected.

(Reporting by Suleiman al-Khalidi Writing by Lisa Barrington; Editing by Toby Chopra) ((lisa.barrington@thomsonreuters.com; +961(0)1954456;))