Baghdad – Residents of a besieged Iraqi town say they have prepared graves for their families and will kill their wives and children if the city falls to the Islamic State group.

The Shia Turkmen of Amerli, a town in the north of Iraq, are resisting Islamic State fighters who have surrounded them for two months. On Saturday, the Iraqi army and Shia militiamen launched an offensive to break the siege, but the fate of those inside still hangs in the balance.

Residents told Al Jazeera that they would rather kill themselves than fall into the hands of the Islamic State group, which has been accused of murdering those from religious minorities. The US and its allies last month intervened to break the siege of thousands of Yazidi tribesmen who were besieged on Sinjar mountain by the Islamic State.

"In every three to four houses we have dug graves. If the Islamic State storms our town everyone will be killing their wives and children and they will bury them," says Mehdi, a government employee reached by phone in Amerli.

Mehdi, who asked for his real name to be withheld, said their wives had agreed they would rather die than be taken captive by the group. "They say ‘we don’t want to end up in the hands of the Islamic State, being enslaved like those in Sinjar mountain….We don’t want the Islamic State to lay their hands on us.’”

Women who have been airlifted from Amerli to Baghdad this week said the only question among their female relatives was whether they would have someone shoot them or do it themselves.

"All the women will kill themselves – either shoot themselves or use kerosene and burn themselves to death," said Fatima Qassim, a beauty salon owner from Amerli.

Fatima said her brother was fighting to defend the town and had remained behind with his wife and six children.

"He put eight bullets in his rifle and he said if ISIS enters the town then I will kill my children one by one and then I will kill my wife and myself."

Her sister Laila said her husband’s sister, Nada, killed herself a few weeks ago after her husband of less than two years died in the fighting.

After 40 days, Nada’s father called to say he was sending her a new husband she believed to be an Islamic State fighter. She took a pistol and shot herself, Laila said.

If the Islamic State storms our town everyone will be killing their wives and children. Mehdi, resident of Amerli .

Despite sporadic airlifts by the Iraqi army to rescue residents, between 15,000 to 20,000 remain in Amerli. Two months under siege has left it short of food and wells are running dry.

An estimated 2,000 men, many of them famers or civil servants, have dug trenches and repelled three assaults.

The US military is expected to begin its own airlifts of food and water to Amerli but has been loath to play the same role in fighting IS forces that it has further north.

Amerli falls outside the declared US mandate of protecting US personnel and interests and critical Iraqi infrastructure.

The United Nations last week said the situation in Amerli was desperate and required immediate action to prevent a possible massacre.

Turkmen officials says they have been the biggest losers in the IS takeover of large parts of northern Iraq.

“More than 40 of the villages surrounding Amerli have fallen to the Islamic State. If the town falls it will be pure genocide," says Torhan al-Mufti, the outgoing minister of communications.