Papua New Guinea military personnel fired shots at Australia's refugee detention centre on Manus Island as an angry mob threw rocks inside its compounds.
The Australian Department of Immigration and Border Protection said one detainee was injured by a rock during the Good Friday incident.
But the Kurdish journalist and Manus Island detainee, Behrouz Boochani, reported three refugees were hurt by projectiles thrown over the fence and that some Australian officials were also injured.
"A refugee from Sudan has been injured in his head and another Sudanese man injured in his chest. A Pakistani refugee has been injured in his stomach and is urinating blood," said Mr Boochani.
The journalist said more than 100 shots were fired at about 7pm local time on Friday, following a fight between asylum seekers and a group of locals at a nearby football field.
The detention centre is situated next to the Lombrum naval base operated by the PNG defence force.
"The problem started when some of the refugees were coming from a soccer game and a man from the Navy who refugees claim was drunk started to argue with them. They started to fight each other and then a lot of young local people and refugees got involved in the fight," said Mr Boochani.
"After a while the refugees ran away to the centre and the local people followed them throwing stones. When the refugees reached the centre both groups started throwing stones and other hard things at each other. Some of the locals started to beat the Australian guards who were outside of the centre and beat them very seriously. They even beat some police officers who were there."
Mr Boochani said Australian personnel closed the gates and left the centre during the incident, before returning after the arrival of PNG police.
PNG immigration officials and police did not respond to requests for comment.
The Australian immigration department said PNG military personnel discharged weapons into the air during the attack, but photos sent by detainees to the Refugee Action Coalition in Sydney showed bullet holes in structures at the centre.
Mr Boochani said bullets hit and entered rooms in Mike and Foxtrot compounds.
The Coalition also supplied a video filmed by a detainee in which gunshots could be heard and guards appeared to fleeing the centre in a vehicle.
The coalition's Ian Rintoul said the Good Friday attack exposed the violence that refugees were condemned to.
"The shooting has been a shocking and stark reminder of the dangerous situation that exists on Manus Island for the almost 900 refugees and asylum seekers that Australia still holds there," said Mr Rintoul.
The Human Rights Law Centre in Melbourne said the terrifying attack was further proof the Australian government must immediately evacuate the centre and bring the detainees to Australia.
"Most of these men were found to be refugees years ago. Last night's attack has left them terrified and - after four years of fear, violence and limbo - they are completely exhausted," said the centre's director of legal advocacy, Daniel Webb.
"Enough is enough. The men on Manus must immediately be evacuated and brought to safety in Australia."
Mr Boochani said Australia's non-security staff like case managers and interpreters accomodated outside the centre were also traumatised by the incident.
"Some of those staff did not come to work today. Last night proved that Australia cannot ensure safety not only for refugees but for its citizens too."
In 2014, a mob stormed inside the detention centre killing the Iranian refugee, Reza Barati and injuring about 60 other detainees.