A pro-ISIS Tweet sent out with a hashtag for a tech diversity conference in San Francisco that was tending on Sept. 11.(Photo: Twitter)

SAN FRANCISCO – Twitter accounts claiming to be affiliated with the Islamic State were piggy-backing on trending Twitter hashtags Friday, the anniversary of the Sept. 11, 2001 attacks.

The Tweets were sent from a variety of accounts and used hashtags such as #we_will_burn_America and #IslamicState. Alongside those hashtags were unrelated ones, such as #techinclusion15 and #remake2015, which were associated with technology conferences taking place in San Francisco.

Some of the tweets sent using the deceptive hashtags included video, such as one purporting to be a firefight between mujahideen and U.S. forces in Iraq. It went out with hashtags for #techinclusion15 and #remake2015 as well as #We_Will_burn_America‪‬.

One of the odder ones was #replacebandwithgoat, a playful topic in which users swap out the word "goat" for a popular band name, resulting in names such as "The Goating Stones."

A search of that hashtag turned up multiple tweets including videos and other information about the Islamic State, such as "Honor is in Jihad: A message to the people of the Balkans."

Several of the Tweets including disturbing images and video, including Humvees being blown up and the bodies of soldiers.

Islamic State-affiliated accounts have been co-opting trending Twitter hashtags since at least the Ferguson protests of 2014, said Veryan Khan, editorial director of Terrorism Research and Analysis Consortium, a private firm that collects information on terrorism.

The senders piggyback on popular topics because it helps get their message out to people who otherwise would never see it, or want to see it.

"Their theory is that no publicity is bad publicity," said Kahn. "They even used #nationalburgerday," she said.

The Twitter accounts are in all different languages and come from all over the world, Khan said.

Twitter says it doesn’t allow tweets that threaten or promote terrorism.

The FBI said it was aware of the tweets as well as threats regarding cyber attacks aimed to coincide with the anniversary of September 11th.

"The FBI takes all threats seriously and will investigate as appropriate," spokeswoman Carol Cratty said.

Read or Share this story: http://usat.ly/1F2F9DN