Israel cut the permitted zone for vessels that fish off the shore of Gaza on Tuesday after a rocket was fired from the coastal enclave into Israel by suspected fighters.
Israel enforces a crippling land, air and sea blockade on the territory, but had extended the fishing zone to the farthest for years at the beginning of April. It was at 15 nautical miles but officials have again reduced it to six nautical miles.
That extension was one Israeli measure implemented to ease tensions with Gaza’s rulers Hamas ahead of Israel’s election on April 9, which was won by incumbent Prime Minister Benjamin Netanyahu. The move came after Egypt-led talks in a bid to calm the situation in the enclave, where anger is widespread at Israel's siege. Cairo has emerged as a prominent mediator in talks between Israel and Hamas.
Cogat, the Israeli defence ministry unit that oversees civil matters in the Palestinian territories said the new limit would be in force "until further notice".
A Cogat spokeswoman said the decision was taken in the light of a rocket launch from Gaza late on Monday.
A military spokeswoman said the rocket fell into the Mediterranean, a few kilometres off the Israeli coast.
The Gaza fishermen's union said the limit was then set at 15 nautical miles in the south near the Egyptian border, at 12 off central Gaza and at six in the north near the Israeli border.
At 12 nautical miles at its furthest point, the zone remained short of the 20 nautical miles agreed to under the Oslo accords of the 1990s.
The distance has fluctuated in recent years from between three nautical miles up to 12 in certain areas.
Israel has fought three wars with Gaza militants since 2008 and has blockaded the territory for more than a decade.
Palestinians in Gaza have for more than a year gathered at least weekly along the border for protests, calling on Israel to end its blockade of the enclave.
Israel says it is protecting its borders and accuses the Hamas, which runs Gaza, of orchestrating the protests.
At least 264 Palestinians in Gaza have been killed by Israeli forces since the protests began.
The majority were killed by snipers during protests, although others were hit by tank fire or air strikes.
Mr Netanyahu largely avoided a military escalation ahead of the election for fear that it would drag him to defeat against former Israeli military chief Benny Gantz.