Supporters of Islamic State militants have tweeted thousands of menacing messages to the United States warning that the jihadist group will repeat the September 11 attacks.

The graphic tweets appear to picture injured and dead US soldiers, the twin towers collapsing and army personnel mourning fallen soldiers using the hashtag #AmessagefromISIStoUS.

Metro UK reported that ISIS supporters had tweeted “you should remember this” with pictures of the 9/11 terror attacks as the US began airstrikes in northern Iraq.

“Will blow your embassys (sic) that the continued attacks on the Islamic state,” one tweet read.

“We will repeat the Sept. 11 attacks with full force because of American intervention in Iraq.”

Using the hashtag #AmessagefromISIStoUS pictures were posted on Twitter warning the US against military action in Iraq. (Twitter)

Pro-ISIS social media users have made poster-style mock-ups of New York in flames.

The tweets reportedly began after the US began bombing ISIS militant targets outside the Kurdish city of Irbil.