The trigger-happy Israeli soldiers killed at least 17 Palestinians and left more than 1,400 injured.
He said the situation in Gaza remains a humanitarian disaster, as reported by CNN.
“The US must play a more positive role in ending the Gaza blockade and helping Palestinians and Israelis build a future that works for all,” he said.
He was not alone in his criticism of Israel.
The Israeli human rights group B’Tselem said: “These are the predictable outcomes of a manifestly illegal command: Israeli soldiers shooting live ammunition at unarmed Palestinian protesters.”
It is Israel’s preeminent peace movement, under the banner “Create hope, stop the next war.”
Peace Now issued a statement condemning what it called the Israeli army’s “trigger happy” policies under orders from the Netanyahu government.
The shooting also drew comments from Human Rights Watch.
The international agency said: “The shocking number of Palestinians killed and hurt by soldiers firing across the Gaza fence raises serious questions about Israel’s longstanding use of live ammunition to police demonstrations.
The Israeli military said it stopped a blood bath by shooting the unarmed Palestinians.
Israel’s defence ministry rejected calls for an inquiry into the incident.
Footage of the incident shows Israeli soldiers shooting at a Palestinian in the back while the latter was trying to run away from the massacre.
The article was sent by Just Foreign Policy.