Israel suspended fuel deliveries to Gaza on Friday in response to border violence which the Hamas-run health ministry said left seven Palestinians dead in the coastal enclave.
The Israeli army said five were shot dead after breaking through the border fence and attacking an army post.
But the Gaza health ministry said seven Palestinians were killed as thousands of protesters approached the heavily-guarded Israeli border.
It said four died along the frontier east of Al-Bureij in central Gaza, two east of Gaza City and one near Rafah in southern Gaza.
It named one of those killed as Mohammed Abbas, who was shot in the head.
It said all the victims were males aged between 17 and 29.
Israeli army spokesman Jonathan Conricus said around 20 Palestinians had crossed the border in an "organised attack" after an explosive device destroyed a portion of the fence.
About five of those who got through the fence assaulted an Israeli army position and were "repelled", he wrote on Twitter.
In response to the violence, Israeli Defence Minister Avigdor Lieberman ordered deliveries of fuel to the Palestinian enclave be suspended.
"Following the serious incidents in the Gaza Strip, the defence ministry orders the immediate halt to the delivery of fuel" to the area, he said in a statement.
Four Israeli tanker trucks had delivered fuel to Gaza on Friday morning before "riots" broke out, Lieberman said.
The suspension comes just days after a United Nations-brokered deal to supply the territory with Qatari-bought fuel came into effect.
The terms of the deal saw Doha, a longtime Hamas backer, pledge to pay $60 million (52 million euros) for fuel to be brought into Gaza over six months to supply the strip's sole power plant.
In a rare interview recently, Hamas's Gaza head Yahya Sinwar encouraged world powers to work with it to ease suffering in the strip.
Jason Greenblatt, US President Donald Trump?s peace envoy, had hailed the fuel agreement.
At least 205 Palestinians have been killed by Israeli fire in Gaza since protests began on March 30.
The majority were killed during border demonstrations, though others have died in airstrikes and tank shelling.
One Israeli soldier has been killed over the same period.
Protesters have sent incendiary devices attached to balloons into Israeli territory during demonstrations, which Israel says has caused hundreds of thousands of dollars-worth of damage to farmland.
The protesters are demanding to be allowed to return to lands now inside Israel, from which their families fled or were displaced during the 1948 war surrounding the creation of the Jewish state.
They are also calling for Israel to end its crippling blockade of the strip.
Israel accuses the enclave's Islamist rulers Hamas of leading the protests and using them as a cover for attacks.
There had been hopes the protests would ease after the UN-brokered agreement to ease the strip's energy crisis took effect this week.
But thousands of protestors again gathered Friday in sites along the border, AFP correspondents said.
They added that Hamas leader Ismail Haniya also attended the protests east of Gaza City and hailed the ongoing demonstrations.
Israel's army said approximately 14,000 "rioters and demonstrators" took part in Friday's protests.