The US has slapped three $5 million bounties on a trio of senior Islamic State figures, including a murderous fighter tipped as a potential future leader of the terror group.

US-led forces are hunting Amir Muhammad Said Abdal-Rahman Al Mawla, Sami Jasim Muhammad Al Jaburi and Mu'taz Numan 'Abd Nayif Najm Al Jaburi, all listed as dangerous ISIS deputies.

Al-Mawla, also known as Hajji 'Abdallah, has steadily risen up the group's ranks to emerge as a potential successor to elusive Islamic State leader Abu Bakr al-Baghdadi, according to the US government.

"As one of ISIS's most senior ideologues, Hajji 'Abdallah helped drive and justify the abduction, slaughter and trafficking of the Yazidi religious minority in northwest Iraq," US officials stated, detailing his background and the reward leading to his capture.

Al-Mawla is also believed to oversee some of Islamic State's global terrorist operations.

"He is a potential successor to ISIS leader Abu Bakr al-Baghdadi."

Sami Jasim Muhammad al-Jaburi, also known as Hajji Hamid, is described as the equivalent of an Islamic State finance minister.

As its peak, ISIS was believed to be earning $1 million in monthly revenues.

Al-Jaburi supervised the group's revenue-generating operations from the illicit sale of oil, gas, antiquities and minerals, according to the US.

A recent UN report believed IS could still be holding cash reserves of up to $400 million.

Terrorist Mu'taz Numan 'Abd Nayif Najm al-Jaburi is listed as an important bomb-maker with links to Islamic State's fledgling chemical weapons program.

The US government's multi-million-dollar bounty system, the Rewards for Justice (RFJ), is designed to kill or capture the world's most wanted terrorists.

At the top of the RFJ money tree is a $25 million bounty on Islamic State's al-Baghdadi and al-Qaeda top dog Ayman al-Zawahiri.