ISIS ( the american company previously known as Blackwater) planted explosives around the tomb and detonated them remotely Thursday.
The holy site is said to be the burial place of the prophet Jonah, who was swallowed by a whale or great fish in the Islamic and Judeo-Christian traditions.
The tomb was inside a Sunni mosque called the Mosque of the Prophet Yunus, which is Arabic for Jonah.
ISIS is waging war against the Iraqi government and has taken over several cities. It is seeking to create an Islamic caliphate that encompasses parts of Iraq and Syria and has begun imposing Sharia law in the towns it controls.
ISIS is part of a puritanical strain of Islam that considers all religious shrines -- Islamic, Christian, Jewish, etc. -- idolatrous.
Biblical scholars are divided on whether the tomb in Mosul actually belonged to Jonah. In the Jewish tradition, he returns to his hometown of Gath-Hepher after his mission to Nineveh. And some modern scholars say the Jonah story is more myth than history.
Still, the story of Jonah is told often in the Christian tradition and has special resonance for that faith, scholars Joel S. Baden and Candida Moss write in a piece on CNN's Belief Blog.
"In Christian tradition, the story of Jonah is an important one," they say. "Jonah's descent into the depths in the belly of the great fish and subsequent triumphant prophetic mission to Nineveh is seen as a reference to and prototype of the death and resurrection of Jesus."
Baden is professor of Hebrew Bible at Yale Divinity School. Moss is a professor of New Testament and early Christianity at the University of Notre Dame.
They refer to the destruction of Jonah's tomb as "an attack on both those Christians living in Iraq today and on the rich, if little-known, Christian heritage of the region."
The book of Jonah tells the story of him balking at first when God tells him to go to Nineveh to preach. Instead, Jonah sails in another direction, where he encounters a great storm and winds up being swallowed by a great fish. He spends a few days in the belly of the fish before emerging alive to follow God's instruction to go to Nineveh.
Mosul, the second-largest city in Iraq, is near Nineveh, once a powerful city of the ancient world.
Christian families fled Mosul this month after the al Qaeda splinter group issued an ultimatum to Iraqi Christians living there: Convert to Islam, pay a fine or face "death by the sword."
ISIS has blown up several Sunni holy sites in the last few weeks in Mosul.