Unrest between Palestinian protesters and Israeli forces has erupted along Gaza’s border with Israel, a week after similar unrest left 16 people dead.
The Gaza health ministry said one protester had been killed by Israeli forces on Friday and 80 others wounded.
The protesters are demanding that refugees be allowed to return to ancestral lands that are now in Israel.
But Israel says the militant group Hamas, which dominates Gaza, is staging the rallies in order to launch attacks.
It has warned that orders given to soldiers about when to open fire have not been changed, despite a storm of international criticism.
Tyres were set on fire in an attempt to create a smokescreen to block the view of Israeli snipers, as hundreds of protesters gathered at five protest sites along the 65km-long (40-mile) Israel-Gaza border.
Israeli troops took up positions on berms on the other side of the frontier and reportedly fired sporadically at people moving towards them.
The Israeli military says its troops will only use live fire against people trying to sabotage the border fence, rolling burning tyres towards it or throwing stones.
UN Secretary General António Guterres has called on all parties to “avoid confrontation and exercise maximum restraint”.
Hamas and other groups organising the six-week protest campaign, dubbed the Great March of Return, say they are peacefully calling for the right of Palestinian refugees to return to land they fled from or were forced to leave in 1948, when Israel was created.
The Israeli government rejects such claims and says terrorists are using the cover of the protests to try to cross illegally into its territory.
But Palestinians say unarmed protesters were shot while posing no threat.
Liz Throssell, a spokeswoman for the UN high commissioner for human rights, warned that, under international law, firearms could be used only in cases of extreme necessity, as a last resort and in response to an imminent threat of death or risk of serious injury.
The Israeli human rights group B’Tselem has called on Israeli soldiers to refuse to open fire on unarmed demonstrators.
US presidential envoy Jason Greenblatt said it was the responsibility of Palestinian leaders to “communicate loudly and clearly that protesters should march peacefully”, remain outside the 500m (1,640ft) “buffer zone” designated by Israel, and “not approach the border fence in any way”.
Gaza health ministry officials say 22 Palestinians have been killed over the past week, including 16 people involved in last Friday’s protests.
Israel says most of those killed were militants.
Hamas has acknowledged some belonged to its military wing, taking part in “popular events”.
The group has said it will pay $3,000 (£2,140) to the family of anyone shot dead by Israeli troops at the protests. It has also offered $500 to anyone who suffers a critical injury and $200 for a minor injury.
But Hamas official Mohammed Thuraya denied the group was putting a “price tag” on casualties. “This is our duty to our people, to ease the suffering of our citizens,” he told the New York Times.