The Philippine Navy said on Sunday that two Vietnamese fishermen were found dead inside their fishing boat that was apprehended over the weekend by sailors on patrol in the waters off Pangasinan province north of Manila.

The Philippine Navy spokesman Lt. Jose Covarrubias said five other Vietnamese fishermen were arrested and are now detained at a police jail in Bolinao, a town on the west coast of the Philippine main Luzon Island.

Covarrubias said the Philippine Navy ship accosted the Vietnamese fishing vessel about 30 nautical miles West of Bolinao for poaching.

Covarrubias said the Vietnamese boat rammed the Philippine Navy patrol ship. he said he could not yet say what caused the death of the two fishermen and if shots were fired during the arrests, saying an investigation is underway to look deeper into the incident.

“As of now we cannot give information regarding the (deaths),” he said.

The Navy ship reportedly towed the Vietnamese boat to Bolinao town, he said.

Lt. Col. Isagani Nato, the spokesman of the Armed Forces of the Philippines’ Northern Luzon Command, said he received unconfirmed reports that shots were fired at sea.

“Accordingly, shots were fired but I cannot confirm that, unless we receive the official report,” he said.

Nato clarified that no clashes took place. “It was not an encounter. What was done was arrest. If you say encounter, there’s a fight. What I can say is they were arrested,” he said.