Iranian and Turkish leaders exchanged sharply opposing views Thursday as they discussed how to deal with the crisis in Syria.
Iranian Supreme Leader Ayatollah Ali Khamenei said Tehran strongly supports reforms in Syria under President Bashar Assad, but visiting Turkish prime minister said Assad can't be trusted and must step down.
The unusual public acknowledgment of sharp differences between the two neighbors came on the second day of a state visit to Iran by Recep Tayyip Erdogan.
Erdogan arrived in Tehran from South Korea, where he attended a nuclear security summit and had talks with President Barack Obama.
Iran is Syria's closest ally, and Tehran has staunchly backed Assad during Syria's year-long uprising.
"Iran will defend Syria because of (its) support of the resistance front against the Zionist regime and is strongly opposed to any interference by foreign forces in Syria's internal affairs," Khamenei told Erdogan. "The Islamic Republic of Iran is categorically opposed to any plan initiated by the U.S. regarding Syria."
Khamenei rejected Turkey's position that Assad must step down.
"We support reforms in Syria. The reforms that began in Syria need to continue," state TV quoted Khamenei as saying.
It was not clear how Erdogan responded to Khamenei, but hours later he told Iran's state TV that Assad's regime can't be trusted.
"If Assad doesn't fear (an election), he should give a ballot box to the people and let parties take shape. (Assad's) Baath should not form a party and must be regarded as a thing of the past," Erdogan said. "We can't put the previous years in front of us."
The U.N. says the year-long conflict in Syria has left more than 9,000 people dead.
Turkey is set to host about 60 countries, including the United States, for a "Friends of the Syrian People" conference in Istanbul on Sunday. The participants will discuss ways to further isolate and pressure Assad, as well as measures to support the Syrian opposition.
Turkey has built close economic ties with Iran and has been at odds with Washington over the best way to get Tehran to halt its nuclear program. Turkey favors a diplomatic solution to the standoff instead of sanctions.
Even so, Turkey has agreed to host a NATO defense shield radar that would send a warning if Iran fires missiles.