GAZA, April 20 (Xinhua) -- As the fourth weekly protest along Gaza-Israel border began Friday, hundreds of Palestinians flew kites over the border fence into Israeli territory as a way to protest.

This week, flying kites was the Palestinians' tool to express their anger against Israel during their six-week protests dubbed the Great March of Return, which kicked off on March 30 and left so far 37 Palestinians dead and hundreds of others injured.

Since early hours of the day, thousands of Palestinians gathered at the eastern area of the Gaza Strip to carry on their anti-Israel rallies that were held in five areas along the borders with Israel.

The marches are expected to peak on May 15, the day after the 70th anniversary of Israel's declaration of independence but marked by the Palestinians as the Nakba Day, or "Day of the Catastrophe."

Close to the border fence, teenager Ahmed Bashir from Gaza city made his own kite bearing the colors of the Palestinian flag and flew it over the Israeli soldiers guarding the borders amid the cheers of his pairs.

"My kite is flying over our stolen lands," Bashir said as he held the kite string. "I wrote 'we will be back' on my kite."

Next to Bashir, teenager Suleiman Abu Khdair attached a letter to his kite.

"My letter is sent to Israeli soldiers. It says 'Leave our homeland'," Abu Khdair told Xinhua while watching dozens of teenagers flying kites along the borders.

The little boy said he is just among thousands of Palestinians who came to participate in the weekly protest that demands the return of Palestinian refugees to their homes they were forced to leave when Israel was created in 1948.

"The Israeli soldiers target us with live ammunition and tear gas, but we reply with these kites," he added.

Palestinians believe that the mass protest is a strong message to the world that the issue of the Palestinian refugees has not been resolved yet.

The Palestinian refugees' struggle to return home has been one of the key and thorniest issues in the final status negotiations between Palestinians and Israelis.

Spokesman for the organizing committee of the protests, Ahmed Abu Retaima, told Xinhua that flying kites is an initiative of young people who wanted to show that the protests are peaceful but are met by violent Israeli reactions.

However, some Palestinians believe that the kites could also be used to cause Israel troubles.

Dozens of young people flew kites carrying firebombs that started fire once they touched the ground, causing wildland fire near the border fence.

"These kites are simple, but they still can cause damage," Eissa Abu Jamie, a masked Palestinian protestor from southern Gaza Strip city of Khan Younis, told Xinhua.

He added that Israelis should realize that what has been seized by force can only be retrieved by force.

According to Israeli media, kites with Molotov cocktails attached to them had caused several fires, but had not caused injuries.

Regional councils of Israeli towns and villages adjacent to Gaza asked Israeli citizens to be alert and to report any unusual fire incidents.

During this Friday rally, four Palestinians were killed and at least 450 others injured in clashes between demonstrators and Israeli soldiers in eastern Gaza Strip.

Among the injured, 96 were shot with live ammunition, of whom 4 are in serious conditions.

Earlier in the day, Israeli army planes threw flyers over eastern Gaza, warning people "not to listen to the incitement of the organizers of the rallies."