ISTANBUL (Reuters) - Turkey wants to join the United States in a military operation to push Islamic State from its Syrian stronghold of Raqqa, as long as it excludes Kurdish rebel forces, President Tayyip Erdogan was quoted as saying on Sunday.

NATO member Turkey, part of the U.S.-led coalition battling Islamic State, is backing Arab and Turkmen Syrian rebels who seized the Syrian town of Jarablus from the jihadists a month ago in an operation it has dubbed "Euphrates Shield."

But Ankara is wary of the U.S.-allied People's Protection Units (YPG) and its political arm, the Democratic Union Party (PYD), Syrian Kurdish groups it sees as extensions of Kurdish militants who have waged a three-decade insurgency on its own soil.

"Our foreign minister and military authorities are in talks with the United States discussing the matter of Raqqa. We shared with them our conditions," Erdogan told reporters on his plane returning from New York, where he spoke at the annual United Nations general assembly and met U.S. Vice President Joe Biden.

"Taking a joint step is important for us," he said, according to private broadcaster NTV. "If the United States does not insert the PYD and YPG into this business, we can fight this battle with the United States."

Turkey has focused much of its energy during the six-year war in neighboring Syria on its desire to oust President Bashar al-Assad rather than fighting Islamic State. Its recent push into northern Syria came after steady advances by the YPG.

But Erdogan said Turkey had exhibited "the most effective struggle against Islamic State, despite the disinformation."

Senior U.S. military officials said last week they were considering arming Syrian Kurdish fighters and acknowledged the difficulty of balancing this with the relationship with Ankara.

Erdogan said he asked Biden about weapons shipments to Kurds and that the vice president said he was not aware of any such deliveries.

(Reporting by Ayla Jean Yackley; Editing by Mark Potter)