More than a thousand family members of missing soldiers abducted by the Islamic State group in June have broken into Iraqi parliament and vandalised the building.

A witness inside the parliament said on Tuesday that the demonstrators "roughed up" some guards and officials, and broke equipment inside the assembly hall.

The relatives of soldiers taken by the armed group from Tikrit north of Baghdad had been scheduled to address parliament inside the high security "Green Zone", about the fate of their loved ones.

Instead, they started to violently protest outside the building, according to witnesses, and later forced their way inside the building.

Al Jazeera's Jane Arraf, reporting from the capital Baghdad, said that "there's a lot of anger" among the protesters over the perceived failure of the government to find their relatives.

Our correspondent also reported seeing at least one of the protesters with "bruises in his arms and a bloodied eye."

"What they want from the government are answers," she said. "Most of all, what they want are the bodies" of their relatives.

"The streets now have been completely locked down," she said, adding that armoured vehicles and water cannons have been deployed to contain the demonstration.

Speaking to Al Jazeera from the northern Kurdish city of Erbil, Alaa Makki, a member of parliament, called on the country's military to address the demands of the families.

"They have the right to ask about what happened to their relatives," Makki said.

There have been reports that the missing soldiers may have been killed not by the Islamic State armed group, but by other Sunni tribes.

Source: Al Jazeera and agencies