Thousands of Palestinians formed a human chain along the border between the Gaza Strip and Israel Wednesday, protesting the Israeli blockade of the territory.

Organizers had hoped to form the chain along the entire 40-kilometre strip but only about 5,000 people showed up -- many of them schoolchildren and university students.

The group, which included many schoolchildren and university students, joined hands outside the town of Beit Hanoun -- about six kilometres from the border.

Signs saying "End the siege of Gaza now," and "Your siege will not break our will," could be seen in the crowd.

"This is a peaceful event aimed to send a message to the world that the people of Gaza want to live in freedom," one of the organizers, independent lawmaker Jamal al-Khoudary, told The Associated Press.

In response, Israel sent thousands of troops and police to the volatile border.

"Israel will not intervene in demonstrations inside the Gaza Strip but it will ensure the defence of its territory and prevent any violation of its sovereign borders," said a joint statement released by Israeli Foreign Minister Tzipi Livni and Defence Minister Ehud Barak.

CTV's Middle East Bureau Chief Janis Mackey Frayer, at the border, said the response was so strong because Israeli officials feared a repeat of last month -- when Hamas militants destroyed part of the Gaza-Egypt border.

"Hundreds of thousands of Palestinians streamed across the border into Egypt and that was the expectation, or the fear, of what could happen today," said Frayer.

Protest organizers said they wanted to focus attention to the Israel-imposed blockade, which has created shortages of vital supplies in Gaza.

The blockade was introduced after Hamas seized control of Gaza last June. Israel has recently introduced stricter sanctions in retaliation to rocket fire by Gaza militants.

Later on Monday, militants fired 11 rockets at southern Israel, military officials said. A 10-year-old boy in the town of Sderot, just across the Gaza border, was seriously wounded. Shrapnel cut through the boy's shoulder, doctors said, but surgeons were able to save his arm.

Israeli government spokesman David Baker criticized the attacks from Gaza.

"Those who raise their hands against Israeli children will be pursued by Israel, and we will take all measures necessary to prevent such attacks on our civilians," Baker said.

Palestinian President Mahmoud Abbas called on the U.S. to follow through on its pledge to work for a Middle East peace settlement by the end of the year. He warned there would not be any future chances.

The U.S. "must understand it is to play an active role, not just as a supervisor, by intervening directly to help make peace," Abbas told reporters in Amman, Jordan, after meeting with King Abdullah.

He also urged the Israeli military to "stop all attacks in the Gaza Strip, including firing missiles there."

Earlier Monday, an Israeli airstrike killed three Hamas militants in southern Gaza, Hamas and Palestinian medical officials confirmed. The Israeli military confirmed the attacks. A fourth Palestinian militant was found dead in the Gaza border town of Rafah.

With files from The Associated Press