Unknown gunmen on a motorcycle shot dead a prominent Iraqi expert near his home in the Iraqi capital on Monday.

Hisham al-Hashemi was shot outside his home and died shortly thereafter at hospital, the local reports said.

Hashemi was a leading expert on extremist factions including the Daesh group.

No group has to date claimed responsibility for the assassination.

Iraqi Prime Minister Mustafa al-Kadhimi vowed to pursue the assailants while holding an outlawed militant group responsible for the killing, according to a statement by the prime minister's media office.

Meanwhile, the U.S. Embassy in Baghdad called on the Iraqi government to bring those responsible for his murder to swift justice.

“The U.S. Mission in Iraq is deeply shocked and saddened by the cowardly murder of respected academic, Dr. Hesham Al-Hashimi.  Our deepest condolences to his family and to the people of Iraq for the tragic loss of this Iraqi national treasure.   We call on the Iraqi government to bring those responsible for his murder to swift justice,” the embassy said in statement on its Twitter account. (ILKHA)