Israeli soldiers killed a Palestinian who approached the Gaza Strip border on Wednesday to demonstrate against a no-go buffer zone imposed there by Israel, witnesses and hospital officials said.

They said the 20-year-old was shot as he and scores of other protesters planted Palestinian flags in the ground near the border fence, east of Gaza City. Some threw stones, drawing gunfire from an Israeli patrol on the far side of the fence.

It was the first death at such demonstrations, weekly events that organisers hope will draw attention to Israel's policy of barring Palestinians from coming within 300 metres (yards) of the border. Those that do risk being shot on sight.

A military spokeswoman said troops had fired warning shots when the protesters threw rocks and lit a fire that threatened to damage the fence. Israeli investigators were looking into the accusation that the shooting killed a Palestinian, she said.

Israel withdrew from Gaza in 2005 following 38 years of occupation. After Hamas Islamists took over Gaza in a 2007 Palestinian civil war, Israel declared it an enemy entity and, with neighbouring Egypt's help, clamped down on its borders.

"These are non-violent demonstrations against the Israeli imposition of the buffer zone," a foreign pro-Palestinian activist who gave her name as Eva told Reuters Television at the protest site. "The Israelis say they can shoot anyone in this area. But it annexes Palestinian farmland. It annexes land where Palestinians live and work."

The Gaza border demonstrations began last month and are modelled on similar protests against land seizures for a barrier Israel is erecting in the West Bank, where Palestinians have also been fighting for a state.

Israel invaded Gaza in a three-week offensive 16 months ago to force an end to rocket fire by Hamas and other groups aimed at towns in southern Israel. But the border remains tense and violent incidents involving troops and militants are frequent.