Pro-Palestine activists have launched #themoneymovement campaign on Twitter in support of the victims of Israeli attacks on Gaza.
Campaigners from all over the world are uploading on the social network pictures of banknotes on which they have written "Free Palestine".
The campaign was originally created in 2011 by a Facebook group that urged people to write "Free Palestine" on Israeli banknotes.
The founder of the movement, Salah Barghouti, said in an interview in July 2011, "Our goal is that these currency notes reach Israeli politicians and even Israeli Prime Minister Benjamin Netanyahu, so that they get the message."
The campaign has been revived following Israel's attacks on Gaza last week.
The Israel Defense Forces (IDF) launched an aerial offensive, known as Operation Protective Edge, last Tuesday to restore calm in southern Israel after the firing of a reported 156 rockets from Gaza.
More than 170 Palestinians, including at least 20 children, have been killed and another 700 wounded since Israel launched its operation.
Israeli Prime Minister Benjamin Netanyahu said air strikes would continue despite the mounting death toll in Gaza.
Palestinian Authority President Mahmoud Abbas has asked the UN for international protection from Israel.
"Our patience has run out. Israel's aggression against the Palestinian people must stop," Abbas said in a speech to the UN representative in the Palestinian Territories.
"We have received deeply disturbing reports that many of the civilian casualties, including of children, occurred as a result of strikes on homes," UN high commissioner for human rights Navi Pillay said in a statement.
"Such reports raise serious doubt about whether the Israeli strikes have been in accordance with international humanitarian law and international human rights law."