Iran's foreign minister flew to Turkey on Tuesday seeking to mend a relationship sorely strained by the Syrian uprising and to secure Turkish help for dozens of kidnapped Iranians.
"Turkey has its links with the opposition in Syria. So we think Turkey can play a major role in freeing our pilgrims," Ali Akbar Salehi told reporters as he arrived in Ankara.
A busload of 48 Iranians was seized in Syria on Saturday. Tehran says they were pilgrims visiting a Shi'ite Muslim shrine, denying suggestions that they were military personnel helping President Bashar al-Assad put down a rebellion.
A Syrian rebel spokesman said on Monday that three of the Iranians had been killed in a government air strike and said the rest would be executed if the attacks did not stop. There has been no word on their fate since then.
The once close ties between the Middle East's two non-Arab powers have been ravaged by events in Syria. Turkey has demanded Assad quit but Iran supports his suppression of the "terrorists" it says are backed by its regional and Western enemies.
Turkish Prime Minister Tayyip Erdogan called comments by Iran's top general Hassan Firouzabadi this week blaming Turkey for the bloodshed in Syria "regrettable" and denied his country has meddled in Syrian affairs.
"The statement by Iran's chief of general staff on a website belonging to the Revolutionary Guards that Turkey, Saudi Arabia and Qatar are responsible for the bloody developments in Syria is worrying and regrettable," Erdogan told members of his party in comments broadcast live by NTV television.
Erdogan also sought to remind Tehran he had been one of its few defenders amid Western pressure to boycott Iran over its nuclear programme, which the United States and others believe is aimed at making an atomic bomb, despite Iran's denials.
"When no one else was by its side, Turkey was the country that stood by Iran, despite everything. Turkey was also the country that defended (its right to) nuclear energy," he said.
"But on Syria, once again I ask the Iranians: Does defending a regime that kills its brothers, and I think it has reached 25,000 by now, suit our values, our beliefs?"
Before Salehi's plane landed in Ankara, the Turkish Foreign Ministry issued a statement in which it called the comments from Firouzabadi "unacceptable and irresponsible."
As Salehi arrived in Turkey, another senior Iranian foreign policy official was in Damascus to reassure Assad of Tehran's support.
"AXIS OF RESISTANCE"
"Iran will not allow the axis of resistance, of which it considers Syria to be an essential part, to be broken in any way," Syrian state television quoted Saeed Jalili, the head of Iran's Supreme National Security Council, as telling Assad.
Reflecting Iran's view that its enemies in the Middle East and the West are backing the Syrian rebels, Jalili, the representative of Supreme Leader Ayatollah Ali Khamenei, said the 17-month uprising was a "conflict between the axis of resistance and its enemies in the region and the world".
The "axis of resistance" refers to Iran's alliance with Syria and Lebanon's Shi'ite group Hezbollah, which fought a month-long war with Israel in 2006, with Iranian and Syrian support. It also includes some Palestinian militant groups.
Assad reiterated his determination to defeat the rebels, affirming "the Syrian people and government's determination to cleanse the country of terrorists", the TV report said.
Assad is a member of the Alawite faith, an offshoot of Shi'ite Islam that has dominated Syrian politics through more than 40 years of his family's rule in a country that has a Sunni Muslim majority.
Iran is the Middle East's Shi'ite Muslim power whose regional influence is viewed with suspicion by its mostly Sunni Arab neighbours in the Gulf.
While Syrian rebels accuse Iran of sending fighters from its Revolutionary Guard to help Assad's forces put down the uprising, Iranian officials have blamed the United States, Turkey and Qatar for the kidnapping of its citizens.
"We do not only blame the terrorists on this issue," Jalili told reporters in comments aired on Iranian television. "All those who help them ... are participants in their criminal actions, and we hold them responsible."
Parliamentary Speaker Ali Larijani, in a speech in parliament aired on Iranian television, said: "In the name of Islam, some of these governments have launched killings and even treat Iranian pilgrims in Syria with violence. These crimes are not something the Iranian nation will disregard.
"The American regime and some countries in the region are responsible for these crimes. And they will receive their response in turn."