Iran is spending billions of dollars in support of President Assad of Syria, creating a rift at the top of the regime in Tehran as the war remains deadlocked, according to The Times.

The high level of spending on a conflict whose outcome remains decidedly undecided has caused a rift between Iran's Supreme Leader Ayatollah Ali Khamenei and his spy chief Qassem Suleimani, who had promised that Iranian support would crush the uprising, according to intelligence seen by the Times.

“Suleimani promised Khamenei that he would turn the situation in Syria around and has failed to deliver,” a Western defence source told The Times.

According to the report, the ongoing conflict has caused Iran explore ways to hedge its bets should Assad fall, reopening talks with opposition groups such as the Syrian Muslim Brotherhood.

“They need time to build the necessary alliances to make sure that Iran is not expelled from Syria forever,” a defense source said.