Nigeria's Senate has opened an investigation into the killing of at least seven people by security forces in Abuja in what authorities said was a gunbattle with Islamist militants but witnesses said was an attack on unarmed squatters.
Nigeria's SSS intelligence service said its forces had been searching an area near a residential compound for lawmakers on Friday after a tip-off from arrested members of the Islamist sect Boko Haram, when they came under fire and shot back.
Several witnesses interviewed by Reuters at a hospital where some of the dead and wounded were taken said security forces stormed a house owned by a military man which was occupied by about 100 squatters and opened fire.
There were no security agents at the hospital, as might have been expected if wounded Boko Haram suspects were there.
"The deadline given to them to vacate the property had not expired whereupon the owner of the property, allegedly a highly placed security official, leveraged the... SSS and army to forcefully eject the squatters," Zamfara state Senator Sahabi Yau said late on Tuesday. His comments were broadcast on TV channels on Wednesday.
Yau proposed the motion setting up the Senate investigation.
An SSS spokeswoman did not immediately respond to a request for comment.
If Boko Haram, which wants to impose Islamic law in northern Nigeria, did open fire, it would be the first clash involving the Islamists in the capital this year.
The four-year insurgency by Boko Haram has killed thousands and is seen as the gravest security threat to Africa's top oil producer, but Nigerian forces are often accused of executing suspects then labelling them Boko Haram as a cover up.
"What we want are facts and details of what happened," Senate President David Mark said, urging lawmakers not to speculate until the committee reports in a week's time.