Six people are being treated for gunshot wounds after violence broke out at a meeting of the main opposition party in the Dominican Republic.
Dominican Revolutionary Party (PRD) leader Miguel Vargas blamed the incident on former president Hipolito Mejia, who denied any responsibility.
Mr Mejia was expelled from the PRD earlier this month for insubordination.
The two men have been fighting over the leadership of the party for more than a year.
Mr Vargas accused Mr Mejia of hiring "a mob", which he said fired the shots in an attempt to take over the party headquarters.
Mr Vargas had convened a meeting of the party's executive for Sunday morning, warning Mr Mejia and three other politicians, who have also been expelled, to stay away.
A group of people stormed the meeting and television pictures showed men hitting each other with plastic chairs while another man could be seen limping away with a gunshot wound to his leg.
Police spokesman Maximo Baez said the security forces had retaken control of the PRD headquarters and would investigate the incident.
Mr Mejia, who governed the country from 2000 to 2004, arrived at the party headquarters shortly after the fighting.
He said the police investigation would reveal who was behind the incident.
Mr Mejia ran for president in May 2012 but lost to Danilo Medina of the Dominican Liberation Party.
He blamed his loss on Mr Vargas, accusing him of having formed a pact with Mr Medina.
Mr Mejia, for his part, has accused Mr Vargas of trying to oust him as party leader.