The latest reports from Iraq are among the most horrific seen since Islamists forced out of al-Qaeda for being too bloodthirsty took control of Mosul, the country's second most populous city.

Mohammed Shia al-Sudani, the Iraqi minister for human rights, told the Reuters news agency, there was "striking evidence" 500 members of the Yazidi minority had been killed by the Islamic State (IS) and 300 women kidnapped as slaves.

The victims were buried in mass graves where women and children were also buried alive.

"We have striking evidence obtained from Yazidis fleeing Sinjar and some who escaped death, and also crime scene images that show indisputably that the gangs of the Islamic States have executed at least 500 Yazidis after seizing Sinjar," al-Sudani said, referring to the traditional homeland of the Yazidis, a part of Iraq's Kurdish minority whose faith can be traced to Zoroastrianism.

"Some of the victims, including women and children were buried alive in scattered mass graves in and around Sinjar."

He went on: "In some of the images we have obtained there are lines of dead Yazidis who have been shot in the head while the Islamic State fighters cheer and wave their weapons over the corpses. This is a vicious atrocity."

The claim that the Islamic State, formerly known as the Islamic State in Iraq and the Levant, is burying people alive represents one of the most truly and utterly horrifying stages of a conflict that has already seen summary executions involving beheadings, crucifixions and mass graves.

But because it is so shocking it deserves to be treated sceptically. The United Nations recently backtracked after it said IS had forced women and girls in Mosul to undergo female genital mutilation, but the story was actually started by an internet hoax, while experts pointed out there was no jihadi tradition of FGM.

Shiraz Maher, a Senior Fellow at King's College London specialising in the Middle East, told i100 there was no record of live burials in other conflicts involving Islamists (Syria, Somalia and Afghanistan) and that people should be "slightly sceptical" about the most recent claim, which has echoes of the Nayirah testimony before the Gulf War.

It's unclear how the minister for human rights in Baghdad would have reliable information about the situation in territory controlled by IS, but clearer why such horrific acts would serve to harm IS and boost the central government, which is desperate for help.

The government in Baghdad is beleaguered, its relationship with the west in tatters, any semblance of unity abandoned and an army of jihadists rampaging across large parts of the country.

The Yazidis are certainly facing a desperate struggle for survival in Iraq's north, having been presented with a "convert or die" ultimatum from IS fighters who regard the minority as polytheistic "devil-worshippers".

The plight of the Yazidis and other Iraqi minorities including Christians under IS rule prompted Barack Obama to authorise US military intervention in Iraq last week; air and drone air strikes taking out an Islamist convoy and artillery pieces that would have been able to bombard Erbil, the capital of the Kurdistan Regional Government, the one part of Iraq that has so far been able to resist the IS advance.

In announcing the military strikes, which accompany humanitarian air drops to the tens of thousands of Yazidis trapped on mountains near Sinjar, Obama twice used the word "genocide", a very specific legal term.

The definition can be found in Articles II and III of the 1948 Convention on the Prevention and Punishment of Genocide:

Article II: In the present Convention, genocide means any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group, as such: (a) Killing members of the group; (b) Causing serious bodily or mental harm to members of the group; (c) Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part; (d) Imposing measures intended to prevent births within the group; (e) Forcibly transferring children of the group to another group.

By this definition, the Islamic State's rhetoric and actions against Yazidis, and Christians, certainly seem to constitute genocide, and Obama would have chosen his words very carefully.

But the west's record on intervening to prevent genocide is very sketchy.

More than 100,000 people died in Bosnia-Herzegovina between 1992 and 1995, while around the same time 800,000 Rwandans, mostly from the Tutsi minority, were killed in 100 days.

In Rwanda, the killings were exacerbated by misinformation spread on public radio, as reports of atrocities were matched by actual atrocities as acts of revenge.

There is a very real chance that the latest horrific claims of Yazidis being buried alive is true, which makes the case for further western intervention that much stronger.

There is also a chance they are a result of misinformation, or deliberate attempts to spread rumours about IS, which is already about as barbaric as it gets.