Iran said Tuesday that it was holding the United States responsible for the lives of 48 of its citizens taken hostage in Syria, following an unconfirmed report by a Syrian rebel group that three of them had been killed by shelling.
The foreign ministry, which transmitted its message through the Swiss embassy in Tehran that handles US interests in the absence of Iran-US diplomatic ties, insisted the 48 were pilgrims, not Revolutionary Guards as the rebels claimed.
"Because of the United States' manifest support of terrorist groups and the dispatch of weapons to Syria, the United States is responsible for the lives of the 48 Iranian pilgrims abducted in Damascus," Deputy Foreign Minister Hossein Amir Abdollahian quoted the letter as saying.
He told the official IRNA news agency that "we expect the countries that are in a way responsible for the events in Syria to take the necessary measures to ensure the safety and lives of the Iranian pilgrims and their return to Iran."
He stressed that Iran had appealed for help from both Turkey and Qatar, two governments it accuses of arming the Syrian rebels.
Iran's message was issued after a Syrian rebel group, Al-Baraa Brigade of the Free Syrian Army, claimed on its Facebook page that "three of the Iranian prisoners were killed in fierce shelling" by the army in Damascus on Monday.
The page said the group's leader, Abdel Nasser Shmeir, was threatening to "execute the prisoners who are proven members of the Revolutionary Guard if the shelling continues."
Iran's foreign ministry issued a statement in Arabic, cited by Iranian broadcaster Al-Alam, saying it "rejects as invalid the assertions by the so-called Free Syrian Army that the three Iranian pilgrims were killed during a bombardment by the Syrian military."
The Iranians were taken hostage on Saturday as they travelled in a bus in Damascus.
The rebel group posted a video online on Sunday alleging that the Iranians were elite Revolutionary Guards on a "reconnaissance mission."
But Tehran insists they are some of the hundreds of thousands of Iranian Shiite pilgrims who visit the revered Sayyida Zeinab shrine in the southeastern suburbs of Damascus each year.
Tehran is the staunchest ally of Syrian President Bashar al-Assad, whose forces are locked in nearly 17 months of conflict with rebels his regime describes as "terrorists."
Many of the rebels come from Syria's Sunni majority, which is hostile to the support Shiite Iran has shown to the regime of Assad, whose family is from the minority Alawite sect, a Shiite offshoot.
Iran's parliament speaker, Ali Larijani, said on Tuesday that "the United States and certain countries of the region are responsible for the deaths of the Iranian pilgrims, and they will receive an appropriate response at the right time."