The rights group said on its website on Friday that Israeli soldiers once again used unnecessary lethal force against protesters who posed no imminent threat to them.
Some witnesses have informed HRW that Israeli troops entered Quneitra and the Druze town of Majdal Shams in Syria from the occupied Golan Heights, and then began targeting protesters.
Many demonstrators were shot dead by live ammunition, before Israeli forces even began firing tear gas at them, eyewitnesses told the rights group.
Over 20 protesters were killed and some 325 others were injured in the Israeli attack, medics told the Associated Press.
“Israeli forces quickly resorted to live fire against protesters who entered the demilitarized area … The protesters never posed an imminent threat,” said Sarah Leah Whitson, Middle East director at HRW.
“Israeli troops’ response to the protesters seems to be a perfect inversion of the legal requirement to use lethal force only as a last resort,” she added.
The killing spree came on the 44th anniversary of the ‘Naksa Day’ marking Israel’s occupation of Palestinian lands in East al-Quds (Jerusalem), the West Bank and the Gaza Strip during the Six Day War of 1967.
In a similar incident only three weeks earlier, Israeli forces opened fire on Palestinians who marched to the border areas with Lebanon, Syria and the West Bank to mark the 63rd anniversary of the Nakba Day (day of catastrophe).
At least 15 people were killed and dozens more wounded by Israeli troops on that day, May 15, 2011.