GAZA CITY (Ma'an) -- Israel's navy on Thursday detained four Palestinian fishermen off the coast of northern Gaza, a fishermen's union said.
Union spokesman Niza Ayyash said Israeli gunboats obstructed a Palestinian fishing boat and detained Haytham Ali al-Habeel, his brother Fuad, Saadi Salih al-Adgham and Yahya Jamal Watfah.
The boat was taken to Israel's Ashdod port.
It is unclear why they were arrested.
Palestinian fishermen are only allowed to go three nautical miles from Gaza's shore, even though Israeli-Palestinian agreements previously settled on 20 nautical miles.
Israeli naval forces frequently harass Palestinian fishermen who near the three-mile limit, as well as those inside the zone.
An Israeli army spokeswoman said a Palestinian vessel deviated from the designated fishing zone, and Israeli forces shot warning shots in the air.
Once the fishermen failed to comply they opened fire in the vicinity of the vessel, she said. This halted the boat's progress and the fishermen were transferred to security investigation.