More than a dozen Palestinians are reported to have been killed and hundreds of others injured in clashes with Israeli forces in Gaza.
It comes as thousands of Palestinian protesters begin a six-week demonstration dubbed the 'March of Return', in support of refugees expelled from their homes.
The Times of Israel reported 15 Palestinians were killed and more than 1,000 injured during clashes at the Israel-Gaza border today.
Tear gas, rubber bullets and live fire are said to have been used by Israeli security forces.
Palestinian President Mahmoud Abbas declared a national day of mourning for Saturday after one of the deadliest days in the region in recent years.
The Israeli Defence Forces alleged there were 'violent riots' along the security fence at the Gaza Strip, claiming protesters were rolling burning tires and throwing stones at the fence and troops.
In response to violent riots along the security fence in the Gaza Strip, GOC of the Southern Command, Maj. Gen. Eyal Zamir said: "We're identifying attempts to carry out terror attacks under the disguise of riots. We urge Gazans to stay away & warn the Hamas terror organization."
— IDF (@IDFSpokesperson) March 30, 2018
Around 20,000 people are believed to have attended today's demonstrations, with IDF estimates putting the figure as high as 30,000.
Palestinian flag flies at the Palestinan side of the Israel Gaza borders while Israeli soldiers stand guard on the Israeli side during a tent city protest along the Israel border with Gaza. Picture by: Mohammed Talatene/DPA/PA Images
Organisers of the 'March of Return' - including Hamas - have called for peaceful protests, with thousands of Palestinians expected to take part in the demonstrations.
The march began today on March 30th to mark Land Day - a day of commemoration to mark the deaths in Israel of six unarmed Arab protesters in 1976.
Demonstrations are set to end on May 15th, when Palestinians commemorate the anniversary of the creation of Israel (known by Palestinians as the 'Nakba' or 'catastrophe').
In a statement this week, Israel's foreign ministry claimed: "While the campaign is being presented to the world at large as a peaceful enterprise, there is no doubt that this latest Hamas ploy is aimed at igniting a violent confrontation with Israel."