A top military aide to supreme leader Ayatollah Ali Khamenei on Saturday accused Ankara, Riyadh and Doha of serving US and Israeli interests in Syria, in a veiled warning to Turkey of worsening ties.
"The Americans, Israelis, and some European and Persian Gulf nations, in particular Qatar and Saudi Arabia, have delegated to Turkey the task of achieving their goal to weaken or topple Bashar al-Assad's government or make it surrender," Fars news agency reported General Yahya Rahim Safavi as saying.
"Qatar, Saudi Arabia and Turkey are acting in the interests of the US and the Zionists to weaken the resistance axis comprising Iran, Syria and Hezbollah," said the former Revolutionary Guards commander.
He was referring to the Shiite armed militia in Syria's neighbour Lebanon, dubbed by Tehran's nemesis Washington as a terrorist organisation.
Syria, whose government is Tehran's key Middle East ally, has been engulfed in a 15-month crisis in which the United Nations says more than 10,000 people have been killed. Syrian activists put the death toll at more than 13,000.
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Calling Turkey "a strategic competitor of Iran," Rahim Safavi said that Iran-Turkey relations are still "good."
But in in a veiled warning, he added: "We hope that America and the Zionists will not be able to disrupt relations" between Tehran and Ankara.
For the past two years, Turkey has acted as an intermediary between Iran and world powers on the Islamic republic's controversial nuclear programme of uranium enrichment.
Tehran denies Western allegations that its atomic ambitions include a covert weapons project.
But Turkey's position on Syria, with Ankara calling on Assad to step down to end the bloody strife there, has soured bilateral relations for several months.
Syria's opposition has accused Iran of supplying weapons and military aid to Damascus, while Tehran makes the same allegations against the West and the Gulf monarchies, accusing them of arming the rebels with Ankara's help.
Tehran has repeatedly voiced its backing for international envoy Kofi Annan's six-point peace plan for Syria, calling it the only way to end the crisis, while Gulf nations have condemned Damascus's deadly crackdown.