UN Secretary-General Antonio Guterres has called for an independent and transparent investigation into the violent clashes between Israeli forces and Palestinians in Gaza killing 16 protesters.
The UN chief on Friday appealed to those concerned to refrain from any act that could lead to further casualties and, in particular, any measures that could place civilians in harm's way, Guterres' deputy spokesman Farhan Haq said in a statement.
This tragedy underlines the urgency of revitalising the peace process aimed at creating the conditions for a return to meaningful negotiations for a solution that will allow Palestinians and Israelis to live side by side peacefully and insecurity, Xinhua news quoted the UN chief as saying.
Hundreds were injured in Friday's clashes on the border fence in Gaza.
Thousands of Palestinians started the first day of the Great March of Return, a month-long sit-in staged along the border fence between the Gaza Strip and Israel to demand the return of Palestinian refugees who were forced to leave their cities during the Arab-Israeli war in 1948.
The Israeli Defence Forces (IDF) said in a statement that around "17,000 Palestinians were rioting in five locations along the Gaza Strip security fence", reports Efe news.
Earlier on Friday, a Palestinian was killed and another injured by Israeli tank fire in southern Gaza.
The Land Day tradition was spurred by the events of March 30, 1976, when Israeli forces fatally shot six Palestinian protesters.
More than half of Gaza's two million people are refugees or their descendants, according to the UN.