Palestinian officials say 15 people have now been killed in a day of protest on the Gaza border, with nine shot dead by Israeli army fire and a farmer killed in a separate incident involving pre-dawn tank fire.

In what was the deadliest day for the ongoing conflict since clashes in Gaza last autumn, the Palestinian health ministry said at least another 1,000 Palestinians were injured by a combination of tear gas, rubber-coated steel pellets and live rounds.

Ahead of the start of a day of protests called by the militant group Hamas, a Palestinian farmer was killed by an Israeli tank shell as he worked in a neighbouring field, the ministry said.

Israel had bolstered its security at the border ahead of the expected mass sit-ins, which mark the anniversary of the Palestinians’ “Land Day”, and the start of a month and a half of demonstrations over lost land in Gaza.

The Israeli military said Palestinians rolled burning tyres and threw stones at Israeli forces who then retaliated with tear gas and fire at “main instigators”.

Ahead of the protests, called for by Gaza’s militant Hamas rulers, Israel’s military said it doubled its standard troop level along the border, deploying snipers, special forces and paramilitary border police units, which specialise in riot control.

Hamas had said the activities would be peaceful and the chief Israeli military spokesman, Brigadier General Ronen Manelis, said Israel wanted to avoid violence.

The Israeli military said troops directed tank fire towards two suspects who approached the fence along the southern Gaza Strip and acted suspiciously. It said it would not not tolerate damage to the barrier and that it will hold Hamas responsible.

The sit-ins are seen as a new attempt by Hamas to break a crippling, decade-old Gaza border blockade by Israel and Egypt that has made it increasingly difficult for the Islamic militant group to govern.

Other tactics over the years, including cross-border wars with Israel and attempts to reconcile with political rival Mahmoud Abbas, the West Bank-based Palestinian president, have failed to end Gaza’s isolation.

In the planned protest, Palestinians are setting up tent camps along the border, the first of a series of actions planned in Gaza in the coming weeks.

The activities are to culminate on 15 May, the 70th anniversary of Israel’s creation, with a march through the border fence.

Palestinians commemorate the date as the anniversary of their mass displacement and uprooting during the 1948 war in the Middle East over Israel’s creation. The vast majority of Gaza residents are descendants of Palestinians who fled or were driven from communities in what is now Israel.

Palestinians clash with Israeli troops during mass demonstrations Show all 10 1 /10 Palestinians clash with Israeli troops during mass demonstrations Palestinians clash with Israeli troops during mass demonstrations Palestinian protesters flee from teargas AFP/Getty Palestinians clash with Israeli troops during mass demonstrations Israeli soldiers stand as Palestinian protesters gather on the Israel Gaza border AP Palestinians clash with Israeli troops during mass demonstrations A Palestinian is carried on a stretcher after being injured during the demonstration AFP/Getty Palestinians clash with Israeli troops during mass demonstrations Israeli soldiers take aim as they lie prone over an earth barrier along the border with the Gaza strip in the southern Israeli kibbutz of Nahal Oz as Palestinians demonstrate on the other side commemorating Land Day AFP/Getty Palestinians clash with Israeli troops during mass demonstrations Palestinian paramedics evacuate an injured man on the Gaza side of the Israel-Gaza border Reuters Palestinians clash with Israeli troops during mass demonstrations Palestinians demonstrate with crossed-out posters depicting Israeli Prime Minister Benjamin Netanyahu and US President Donald Trump, during a tent city protest near Khan Yunis in the southern Gaza Strip AFP/Getty Images Palestinians clash with Israeli troops during mass demonstrations Palestinian protesters flee from teargas AFP/Getty Palestinians clash with Israeli troops during mass demonstrations Israeli soldiers shoot tear gas grenades towards the Palestinian tent city protest commemorating Land Day AFP/Getty Palestinians clash with Israeli troops during mass demonstrations Palestinian protesters take cover from Israeli troops AP Palestinians clash with Israeli troops during mass demonstrations Palestinians chant slogans as they attend a demonstration near the Gaza Strip border AP

Eighty-year-old Mansi Nassar walked towards the border with the aid of his cane, ignoring calls to remain 700 metres (2,300 feet) from the barrier.

“I was born in Beit Darras inside Palestine and I will accept no less than returning to it,” he said, referring to his former home village just south of the modern Israeli city of Ashdod. The village no longer exists.

The farmer killed on Friday was identified as 27-year-old Amr Samour. The Palestinian health ministry said he was killed in the south-eastern corner of Gaza.

Yasser Samour, a relative and fellow farmer, said Mr Samour was harvesting parsley before dawn, in hopes of selling it fresh in the market later in the day.

“I was working on the next field,” Mr Samour said. “We heard shelling landing on the field where Amr works. We ran there and found him hit directly with a shell. We were more than a kilometre away from the border.”

Another farmer was wounded in the leg by shrapnel, Mr Samour said.