ANKARA - Iranian Foreign Minister Ali Akbar Salehi is to visit Turkey on Tuesday for previously unscheduled talks expected to focus on Syria and a group of Iranians seized by rebels there, an Iranian diplomat in Ankara said.Iran has stood by its ally Syria despite the growing international pressure on President Bashar Assad, while Turkey has been among his fiercest critics demanding he stand down to defuse a 17-month uprising against his rule.Iran has asked Turkey, as well as Qatar, to help secure the release of 48 Iranians seized by rebels in Syria on suspicion of being military personnel. Tehran says are pilgrims.A Syrian rebel spokesman said on Monday three of the Iranians had been killed in a government air strike in Damascus and warned the rest of them would be executed if the attacks did not stop. There has been no word of their fate since then.Syrian rebels fighting to topple Assad accuse Iran of sending fighters from its Revolutionary Guard to help Assad's forces put down the 17-month uprising.Tehran denies the charge and says the group was on a religious pilgrimage to Syria. Iranian media said on Saturday that the 48 were abducted from a bus in Damascus, the latest in a string of kidnappings of visitors from the Islamic Republic.Tehran has accused Turkey and Qatar of helping rebels fighting to topple Assad, a close ally Iran has praised for promising political reforms. Several Iranians previously abducted in Syria have been released to Turkish authorities before returning to Iran.In a sign of Tehran's diplomatic efforts to secure the release of its nationals, the secretary of Iran's National Security Council, Saeed Jalili, flew to Damascus on Tuesday after ending a visit in Beirut.A Turkish foreign ministry official confirmed the visit, during which he said regional issues will be discussed in talks with Foreign Minister Ahmet Davutoglu."It is expected that the talks will take up the Syrian issue and the situation of the pilgrims kidnapped in Damascus, as well as bilateral issues," the Iranian diplomat told Reuters.He said Salehi was expected to arrive in the afternoon and leave again on Tuesday.