A Palestinian fisherman went missing Wednesday night after his boat collided with an Israel Navy ship in the waters off the coast of the Gaza Strip, the army said.

The Israel Defense Forces said the incident was an accident caused by sea conditions, while Palestinians claimed the navy vessel had intentionally “attacked” the ship belonging to Muhammad al-Hissi.

Nizar Ayyash, head of the Gaza fishing union, told the Palestinian Ma’an news site that the incident occurred at approximately 10:30 p.m. off the coast of Beit Lahiya in the northern Gaza Strip, and that al-Hissi was reported missing shortly afterward.

Both the Israeli Navy and Palestinian sailors launched searches for al-Hissi, who remained missing as of Thursday afternoon.

According to the army, the navy boat in question was escorting a different fishing boat that had “deviated” from the permitted fishing zone. While bringing that boat toward shore, the navy ship collided with al-Hissi’s boat, sinking it.

Al-Hissi’s boat “was not visible [due] to the conditions out at sea,” an army spokesperson said.

“The incident is being reviewed,” she said.

As part of Israel’s naval blockade on the Gaza Strip, Palestinian fishing vessels are forbidden from sailing more than six miles from the shore, though this has occasionally been extended during peak fishing seasons.

Those fishermen that do stray from the designated zone are either warned to go back or escorted to the Ashdod port for questioning.