Editor’s Note: This story contains graphic images.

BELAWAN, Indonesia (AP) — Religious and ethnic tensions running high in Myanmar boiled over far outside the country’s borders Friday, when Buddhist fishermen and Muslim asylum seekers from the country brawled with knives and rocks at an Indonesian immigration detention center, leaving eight dead and another 15 injured.

The melee broke out in North Sumatra province, where more than 100 Rohingya migrants — most intercepted off Indonesia’s coast after fleeing their homeland in rickety boats — and 11 Buddhists accused of illegal fishing were being housed together, said local police chief Endro Kiswanto.

Muslims and Buddhists Brawl With Knives and Rocks in Indonesia

Indonesian police officers carry the body of an illegal migrant from Myanmar upon arrival at a hospital in Medan, North Sumatra, Indonesia Friday, April 5, 2013. Police said a violent brawl between Buddhist and Muslim asylum seekers from Mynamar in an immigration detention center in Belawan of North Sumatra early Friday leaving eight dead and 15 injured. (AP Photo/Binsar Bakkara) 

He said witnesses told police the clash started early Friday after a Rohingya Muslim cleric and a fisherman got into a heated debate about sectarian violence that erupted last month in central Myanmar when mobs of armed Buddhists torched Muslim-owned homes and shops, killing dozens and forcing thousands to flee.

Insults were traded, and the cleric was allegedly attacked by a fisherman, said Yusuf Umardani, the detention center chief. When the cleric screamed, his friends jumped in to help. From there, the rumble broke out so quickly, security guards were too late to stop it.

“The violence took place so fast, and it was completely unexpected because they had been living peacefully here so far,” Umardani said. “Most of the dead victims suffered severe head injuries. Apparently, they fought using anything that they could get — rocks, wood, chairs and knives.”

Eight Buddhists were killed, and 15 Rohingya were injured. Three other Buddhists escaped unharmed, Kiswanto said.

“Our friends were covered in blood,” surviving fisherman Win Thike Oo told an Associated Press photographer at the scene. “If we were there at the time, we would also be dead.”

Muslims and Buddhists Brawl With Knives and Rocks in Indonesia

Indonesian police officers carry the body of an illegal migrant from Myanmar upon arrival at a hospital in Medan, North Sumatra, Indonesia Friday, April 5, 2013. Police said a violent brawl between Buddhist and Muslim asylum seekers from Mynamar in an immigration detention center in Belawan of North Sumatra early Friday leaving eight dead and 15 injured. (AP Photo/Binsar Bakkara)

About 280 people are crammed into the overcrowded detention center — more than double its capacity. It is filled with a mix of mostly asylum seekers from different countries including Afghanistan, Sri Lanka and elsewhere.

Boatloads of Rohingya have been washing up on Indonesia’s shores following a wave of violence last year in western Myanmar, where they are considered illegal Muslim settlers from neighboring Bangladesh. Hundreds have been killed and more than 100,000 left homeless in clashes between ethnic Rakhine Buddhists and Rohingya.

The tensions have tested Myanmar’s fledgling reformist government as it attempts to institute political and economic liberalization after nearly half a century of military rule.

“We actually don’t understand about what is happening in my country,” said survivor Oo, who has been detained for nine months at the center after being nabbed for illegal fishing in Indonesian waters. “We are only fishermen. We don’t care about politics or conflict.”

All of the victims from the detention center were rushed to a hospital in the provincial capital, Medan, about 23 kilometers (14 miles) south of the port town of Belawan. The three surviving fishermen have been moved to a separate building and hundreds of police have been deployed to secure the center. A forensics team was working to collect evidence and surveillance recordings were being reviewed.

Muslims and Buddhists Brawl With Knives and Rocks in Indonesia

Photo Credit: AP

The UN Refugee Agency issued a statement saying it was saddened by news of the deaths.

“UNHCR is calling for calm among the groups and urging the Indonesian authorities to take action to prevent further violence, including moving individuals into community housing as soon as possible,” it said.

Kiswanto said 25 Rohingya were being questioned by police and would be prosecuted under Indonesian law if suspected of being involved in the killings.

Maj. Zaw Htay, the director of the president’s office in Myanmar, said the country’s embassy in Jakarta has urged Indonesian authorities to investigate and punish those involved.