The United States has claimed that it will not cooperate with Iran's military to fight against the Islamic State (IS) militants in Iraq.

A spokeswoman from U.S. state department said that Washington was not interested in sharing intelligence services with Iran, reported the BBC.

Iranian sources earlier said that Iran's Supreme Leader Ayatollah Ali Khamenei had sanctioned a top commander for such contacts.

However, Iran's foreign ministry said that the report was false. The ministry's Spokeswoman Marziyeh Afkham further said that Iran was critical of U.S. airstrikes after the IS militants had sent threat messages to the States.

The U.S. airstrikes had helped Iranian backed Shia militia and Kurdish forces last month to break months long blockade by IS group on the town of Amerli.