Iran's top leader Ali Khamenei is against US intervention in neighboring Iraq, where extremists ISIS militants opposed to Tehran have seized a number of towns and cities.

"We strongly oppose the intervention of the U.S. and others in the domestic affairs of Iraq," Khamenei was quoted as saying by the IRNA state news agency on Sunday, in his first reaction to the crisis.

"The main dispute in Iraq is between those who want Iraq to join the U.S. camp and those who seek an independent Iraq," said Khamenei, who has the final say over government policies. "The U.S. aims to bring its own blind followers to power."

Shiite Iran supports the Shiite-led government in Baghdad, and has said it would consider any request for military aid.