Speaking at the conference of J Street, a liberal Jewish group that describes itself as pro-Israel and pro-peace, Sanders criticised Saudi Arabia for its lack of support for Palestinians.
Speaking at the conference, Sanders said: "I say to the crown prince and the other multi-billionaire leaders in the region, stop just talking about the poverty and distress in Gaza, do something meaningful about it. I heard the other day that the Saudi king pledged $50 million to UNRWA, the UN agency that works with Palestinian refugees. Fifty million dollars is not a small sum of money, but let us not forget that it is ten percent of what the crown prince paid for a yacht."
The Saudi crown prince, Mohammad bin Salman, who claims to be leading a campaign against corruption in his country, has been criticised for his lavish spending, including the purchase of a $450 million Da Vinci painting last year.
During a US tour earlier this month, bin Salman announced deals worth billions of dollars with American companies.
Sanders, a former presidential candidate who has become a leading figure in left-wing U.S. politics, also denounced Israel for its deadly crackdown on peaceful protesters in Gaza.
He said Israel "massively overreacted" to Palestinian protests over the past month, adding, "Frankly it’s amazing to me that anyone would find that point controversial" .
Bernie Sanders also condemned Israel for its "inhumane blockade of Gaza".
The United Nations has said that the Palestinian enclave of two million people, where youth unemployment is over 60 percent, is becoming "unlivable".
Palestinian Ambassador to Washington Husam Zomlot, who also spoke at the conference, said the Palestinian Authority is committed to the two-state solution but would not abandon Al-Quds (Jerusalem).
Zomlot said: "No state without Al-Quds (East Jerusalem), and no state without resolving the issue of refugees."
