Israel's defense ministry says the country has started to construct a marine barrier along the Gaza border to stop Palestinians, especially Hamas militants, from entering its territory.
It said the underwater barrier is being built a few kilometers north of Gaza and is due to be completed by the end of the year.
Israel's defense minister said the obstacle was the only one of its kind and would put a dent in Hamas' strategic capabilities.
The 2014 Gaza war, Israeli forces killed four Hamas militants who had managed to infiltrate by sea.