Authorities in Germany's Berlin imposed a ban on the Palestinian keffiyeh scarves in schools, claiming that it could pose a threat to peace, amid Israel's ongoing inhumane blockade against the Gaza Strip, where civilians are trapped with nowhere to go.

"Any demonstrative behavior or expression of opinion that can be understood as advocating or approving the attacks against Israel or supporting the terrorist organizations that carry them out, such as Hamas or Hezbollah, represents a threat to school peace in the current situation and is prohibited," Education Senator Katharina Guenther-Wuensch said in a letter to schools.

Besides direct symbols of Hamas or Hezbollah, as well as depictions and statements glorifying violence, the ban also extends "symbols, gestures and expressions of opinion that do not yet reach the limit of criminal liability" which includes the keffiyeh.

The official also outlawed "free Palestine" stickers with inscriptions or a map of Israel in the colors of Palestine.

"Such actions and symbols endanger school peace in the current situation," Guenther-Wuensch said.

Clashes are said to have taken place at schools in the German capital in recent days because of Israel's massive bombing on Gaza.

Critics say the actions by the authorities violate constitutional rights, freedom of association, and the right to demonstrate.

Earlier this week, Initiative Palestine accused Berlin police of banning pro-Palestinian rallies "on racist grounds."

"However, we will not be silenced. We will inform about upcoming steps to bring (the) Palestine (issue) to the streets of Berlin," the group said on its website.

Palestinian group Hamas launched Operation Al-Aqsa Flood against Israel on Saturday, a multi-pronged surprise attack that included a barrage of rocket launches and infiltrations into Israel via land, sea and air.

In retaliation, the Israeli military then launched Operation Swords of Iron against Hamas targets within the Gaza Strip.

A symbol of Palestinian nationalism, the keffiyeh's history goes back to the Arab revolt in Palestine in the 1930s.