Work began Sunday on the construction of a fortified marine wall to prevent terror attacks from the Gaza Strip via the sea, the Defense Ministry said in a statement.

The barrier, constructed in the area of Zikim beach, is designed to withstand the battering of the water and to be in use for many years, the ministry said.

Construction of the barrier, described by the ministry as an “impregnable breakwater,” is expected to be finished by the end of the year. The statement did not say how much the barrier will cost.

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It will have three levels: one under the water, then a level of armor stone, known for its durability, and barbed wire along the top. The entire barrier will itself be protected with another wire security fence.

Defense Minister Avigdor Liberman said the barrier would deny the Hamas terror group another strategic capability.

“Today we began setting up a sea barrier, the only one of its kind in the world, which will block the possibility of infiltration from Gaza to Israel via the sea,” Liberman said in the statement. “This is an additional setback for Hamas, which has lost another strategic capability that it has invested massive amounts in developing. We will continue to protect the citizens of Israel with might and sophistication.”

The decision to build the barrier was prompted by an attack carried out during the 2014 war in Gaza. On July 8, 2014, four Hamas naval commandos swam ashore outside Kibbutz Zikim on Israel’s southern coast.

The frogmen brought with them automatic weapons, fragmentation grenades and explosives, the latter of which they used against an Israeli tank, unsuccessfully. Some 40 minutes after they came in from the surf, the Hamas operatives were killed in a combined attack from the sea, ground and air.

Initially presented by the military as an unmitigated victory, a leaked IDF review of the incident later showed the army’s response to be slower than previously thought and the Hamas commandos’ attack to be more accomplished than it had seemed.

The defensive sea shield comes in addition to work that began last year on a massive barrier Israel is constructing along its land border with the Gaza Strip.

The work on the 37-mile (60-kilometer) barrier began in 2016 and is expected to be finished around the end of next year. It will feature an advanced underground protection system that extends dozens of meters below the ground — the army does not reveal the depth — in order to detect and destroy tunnels that attempt to penetrate into Israeli territory, as well as an aboveground metal fence adorned with sensors.

The project is expected to cost approximately NIS 3 billion ($833 million), with each kilometer of the underground portion of the barrier costing approximately NIS 41.5 million ($11.5 million). The aboveground fence is significantly cheaper at just NIS 1.5 million ($416,000) per kilometer.

The military proposed building this barrier, too, following the 2014 Gaza war.

Hamas, a terror group that seeks to destroy Israel, made extensive use of its tunnel networks to send fighters into Israel as well as to move its terrorist operatives and munitions within the Gaza Strip.

During the 50-day campaign, the IDF destroyed some 14 tunnels that entered Israeli territory, along with 18 internal tunnels, and depleted Hamas’s weapons stores.

Since work began on the land barrier the IDF has destroyed several cross-border tunnels.