Iran welcomed as acceptable an Arab peace deal signed by Syria on Monday that aims to end nine months of unrest against the rule of President Bashar al-Assad, a senior official told an Iranian Arabic language news channel.

Whatever is accepted by President Assad is an acceptable act in Iran's view, Iran's Deputy Foreign Minister Amir Abdollahi told Al Alam television.

Of course some modifications could be considered in the plan ... However, many of Iran's standpoints have been considered in the deal, he told the station.

Syria agreed on Monday to let Arab League observers into the country to monitor implementation of a deal it agreed to last month to pull troops from protest-hit towns, free political prisoners and start talking to dissidents.

Tehran describes Syria, its closest Arab ally, as an outpost of resistance to Israel that has been set up by Washington and its lackeys in the Middle East region. Iran refuses to recognise Israel.

Analysts say the collapse of Syria's government would be a blow to Iran as Damascus is the Islamic state's most important bridge to the Arab world.

(Writing by Parisa Hafezi; Editing by Jon Boyle)