The toll in the protests along the Gaza border with Israel has risen to 16, Haaretz reported. More than 1,400 protestors were injured by live fire, rubber bullets and tear gas shelling during confrontations with Israeli forces, according to the Palestinian Health Ministry.

On Friday, some 30,000 Palestinians in Gaza began what they call the “March of Return”, a six-week-long protest demanding that refugees be allowed to return to their homes that are now in Israel. They have pitched five camps along the border with the support of Islamist group Hamas, prompting the Israel Defense Forces to “enforce a closed military zone” in the areas around Gaza.

The clashes intensified overnight, with Israeli fighter jets targeting three Hamas sites after a post of the Israel Defense Forces was targeted in northern Gaza, CNN reported. They used tanks to retaliate after a gunfight.

A spokesperson for the Israeli defense, Ronen Manelis, said they were facing “a violent, terrorist demonstration at six points” along the fence, and that they were using “pinpoint fire” to thwart attempts to breach or damage the security fence, The Times of Israel reported. “All the fatalities were aged between 18 and 30, several of the fatalities were known to us, and at least two of them were members of Hamas commando forces,” he said.

The United Nations Security Council has been warned that the situation in Gaza “might deteriorate in the coming days”. “Israel must uphold its responsibilities under international human rights and humanitarian law,” UN Deputy Political Affairs chief Taye-Brook Zerihoun said. “Lethal force should only be used as a last resort with any resulting fatalities properly investigated by the authorities.”

Palestinians began the March of Return on March 30 because they commemorate the day as Land Day to remember the six protestors who the Israeli forces killed in 1976 during demonstrations over land confiscation. The protest is scheduled to end on May 15, which Palestinians call Nakba (catastrophe) – it marks the day hundreds of thousands of Palestinians were displaced during the conflict over the creation of Israel in 1948.