Brigadier Thulani Ngubane said on Sunday Marikana police were called to a murder scene at Nkaneng, North West on Saturday evening.
"According to the members there were a lot of people gathered there and some started shooting at police and police responded [by firing live ammunition]."
He said the crowd dispersed and they proceeded to the scene.
"We have not received any reports of casualties."
Ngubane said the matter was also reported to Independent Police Investigative Directorate (IPID).
When police arrived at the crime scene they found that two brothers were killed and two women were injured in a shooting.
Looking for information
A group of armed men wrapped in blankets and wearing balaclavas allegedly stormed into a shack on Saturday night.
They apparently asked the two brothers – who were twins – about the whereabouts of another man.
Ngubane said when the brothers said they did not know the man, they were shot.
"The one brother who was shot two times died on the scene, while the other brother died on arrival at the Andrew Saffy hospital."
Two women who were in the shack at the time of the shooting were wounded.
One was shot in the thigh while the other was hit with a panga. They were taken to hospital and discharged on Sunday.
A North West regional organiser of the Association of Mineworkers and Construction Union (Amcu) trade union was also shot an killed in the same area on Saturday evening.
Another man killed
Ngubane said four men, who on Saturday came to Billy's Tavern near Anglo Platinum's Khomanani mine shaft two in Rustenburg and shot and killed the 46-year-old man, remained on the run.
North West premier Thandi Modise condemned the murders.
"Though nothing suggest that the two incidents that occurred near Anglo Platinum's Khomanani mine and Nkaneng informal settlement near Marikana are connected, we wish to reiterate our earlier appeal for calm and call on police not to rest until those responsible for the callous murders are behind bars."
She appealed to members of the public to come forward with information that might assist police in their investigations.
Ngubane said the murders were being investigated and it was be too early to say if they were linked.
"That is still the subject of an investigation at this point. We do not want to pre-empt any of the outcomes."
Victim due to testify at Marikana commission
E.News Channel Africa reported that the Amcu official had been expected to testify before the Farlam Marikana commission of inquiry.
The commission is investigating the deaths of 44 people killed in violence related to a strike at Lonmin's Marikana mine in August last year.
In April this year, Dali Mpofu – who is representing miners involved in last year's police shootings in Marikana at the commission of inquiry – was robbed and stabbed while walking on the beach in East London.
Previously in March, a sangoma, Alton "Ndzabe" Joja, who was meant to testify at the commission was shot and killed outside his home in the Ludeke Holt village in Mbizana.
At Joja's funeral in April, Uncedo service taxi association president Ntsikelelo Gaehler claimed his murder was a result of taxi wars.
Earlier this year, the Farlam commission heard that Joja was believed to have performed rituals on protesting Lonmin mineworkers before the police shooting on August 16. – Sapa