Seven Palestinians were killed and least 350 injured in Israeli firing along the Gaza border on Friday, the Palestinian Health Ministry said. Thousands of Palestinians in Gaza have begun what they call they “March of Return”, a protest demanding that refugees be allowed to return to their homes that are now in Israel, the BBC reported.

Marking the beginning of their six-week-long protest, Palestinians have pitched camps near the border with the support of Islamist group Hamas. The Israel Defense Forces said it had “enforced a closed military zone” in the areas around Gaza. Protestors threw stones and firebombs at the troops posted along the fence, Haaretz reported.

The Israeli force said Palestinians were rioting in six locations in the Gaza Strip, “rolling burning tyres and hurling stones at the security fence and at IDF troops”. It maintained that they are firing only at the “main instigators”.

The Israel Defense Forces has estimated that around 20,000 Palestinians are participating in the march along the Gaza border, The Times of Israel reported. The report quoted unidentified officials as saying that over a thousand were wounded because of tear gas, rubber bullets and live fire.

The Foreign Ministry of Israel called the protest a “deliberate attempt to provoke a confrontation with Israel” and said the “responsibility for any clashes lies solely with Hamas and other participating Palestinian organisations”.

Palestinians began the March of Return on Friday because they commemorate March 30 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.