An Australian Twitter user and supporter of the Islamic State group urged an attack on a Prophet Mohammed cartoon contest in Texas just days before two gunmen attacked the venue and were shot dead by police, it's been reported.
The Melbourne man, known only as "Australi Witness", last week shared a map of the community centre where the event was held while supporting calls for "brothers in Texas" to go there "with your weapons, bombs or with knifes", News Corp reported on Tuesday.
He also posted addresses of synagogues in Australia and the location of Anzac Day services.
"Kuffar (disbelievers) are holding a large Draw Muhammed (PBUH) event in Garland, Texas on May 3rd. Please spread to US brothers," Australi Witness posted.
"Islamic State has a long tale of fanboys and Jihadi wannabes who freely - and are encourage to freely - post on social media. So there's a lot of noise out there. There's a lot of exchange of views," terror expert Greg Barton told SBS.
The Syria- and Iraq-based Islamic State on Tuesday claimed responsibility on its official online radio station, saying "two soldiers of the caliphate" carried out the attack.
"In this case, we have a message that lined up with what actually happened. That may be an important connection, it may just be a coincidence. We don't really know."
Police shot dead two gunmen after they opened fire on a security guard outside the cartoon contest in a suburb of Dallas on Sunday night.
Mohammed cartoon contest organiser 'looking to provoke something'
Mr Barton said the attacks cannot be justified, but believes organiser Pamela Geller was looking to "provoke something" by initiating the cartoon competition.
"It was certainly a provocative thing in the first place to have a public event [that was] highly publicised with a prominent international speaker saying that you going to give a prize to the person who draws the best cartoon of the Prophet.
"It almost looks as it Geller was looking to provoke something to show that America had a problem that she said it did have. She was expecting trouble and may have welcomed it.
"Launching gun attacks on a meeting like this because you don't believe in somebody's views cannot be justified. But provoking such an attack... is also something that can't possibly be justified."
Watch: Interview with terror expert Greg Barton
Controversial Dutch lawmaker Geert Wilders keynote speaker
Controversial Dutch lawmaker Geert Wilders was the keynote speaker at Sunday's Mohammed cartoon-drawing contest, organised by the right-wing American Freedom Defence Initiative (AFDI).
Wilders has been outspoken against Muslims.