Fighters of the Islamic State stand guard at a checkpoint in the Northern Iraq City of Mosul
Fighters of the Islamic State of Iraq and the Levant (ISIL) stand guard at a checkpoint in the northern Iraq city of Mosul, June 11, 2014. Picture taken June 11, 2014. REUTERS/Robert Stringer

An Australian militant has reportedly offered a $1000 bounty to anyone who can give him information about a prominent Muslim leader in Sydney. Authorities have beefed up the security around Dr Jamal Rifi in response to the threat posted on Twitter.

According to reports, the suspected ISIS member was seen in recently uploaded images holding severed heads in Syria. The man believed to be Mohamed Elomar had posted a tweet that since been deleted: "Anyone in Sydney who can give me the details of Habashi dog Dr Jamal Rafi, anything, house details, what area am willing to pay $1000."

The man he was referring to is the outspoken Muslim community leader in Australia who condemned the gruesome images posted on Twitter by Australian jihadist Khaled Sharrouf that showed his son holding decapitated heads.

Reports said that in 2009, Sharrouf was convicted for his role in a planned terror attack in Australia which was then led by the uncle of Elomar. The elderly man is still serving his 21-year sentence. He was also charged for his involvement in manufacturing explosives to be used in a "catastrophic attack."

In July, Australian police had issued warrants for the arrest of Elomar and Sharrouf for posting threatening images on Twitter. The photos were believed to be taken from Raqqa, a Syrian city overrun by ISIS.

In a report by CNN, Rifi said he was "shocked" that he was being targeted. He said he took the threats seriously since the jihadists believed their ideology permitted them to kill him.

Rifi revealed that the NSW police commissioner had called him before sending officers to his home to check on security. Police patrols were intensified in the area.

However, the Muslim leader refused to be deterred by the threat. Rifi had replied to Elomar in a tweet and said, "to know my address just ask your dad, we were in the same soccer team then and we still best mates and he knows I am and never been a Habashi."

On August 14, Rifi and Australia's Grand Mufti Ibrahim Abu Mohamed were interviewed in Arabic and English to denounce the actions of ISIS militants and counter their social media campaign. Rifi urged young people to "forget the rhetoric" and see what ISIS has done as "totally unIslamic."