"Was Israel's response disproportionate? I think it was," he told CNN's Jake Tapper in an interview that aired Sunday on "State of the Union."
"Israel has a 100% -- and no one will fight for that principle more strongly than I will -- has the right to live in freedom, independently and in security without having to be subjected to terrorist attacks," he said. "But I think that we will not succeed to ever bring peace into that region unless we also treat the Palestinians with dignity and respect, and that is my view."
The seven-week conflict
in 2014 was an Israeli response to Hamas rocket fire into southern Israel. More than 2,130 Palestinians were killed in the conflict, and it's not clear how many were civilians. At the time of the ceasefire, the United Nations estimated that more than 70% were civilians, but Israel reported a higher number of militants among the dead.
Tapper asked Sanders about an interview he gave to the New York Daily News earlier this month in which the Vermont senator said his recollection was that more than 10,000 innocent people were killed in the conflict. Sanders told Tapper that he wasn't sure what the death toll was, and when a Daily News editor clarified it to him, he accepted it.
But the claim attracted the attention of the Anti-Defamation League, whose CEO, Jonathan Greenblatt, released a statement on Thursday saying he had spoken with Sanders and that the senator had clarified that his recollection was "inaccurate."
"As you know, the number was much lower," Tapper said.
"Yes," Sanders said.
The Vermont senator then stumbled when Tapper asked Sanders about criticism of Michael Oren, the former Israeli ambassador to the U.S., over Sanders' views of the Gaza clash.
"Who is Mr. Oren?" Sanders asked, apparently unaware of Israel's top diplomat to the U.S. during President Barack Obama's first term.
"Michael Oren, the former ambassador of Israel to the United States. And now he's a politician in Israel," Tapper said.
"I see. And he's attacking me for a statement I did not make," Sanders said.
Later in the interview, Sanders, a secular Jew
, said he hopes to provide a "balanced" view on issues related to Israel and Palestine than most U.S. politicians.
"It is interesting ... that the first Jew in American history to win a delegate, much less a primary, is taking this position with Israel," Tapper told Sanders. "Usually in American politics, everyone just supports Israel whatever Israel wants to do, but you are taking a more critical position."
"I'm taking a more balanced position," Sanders replied.
He added: "Whether you're Jewish or not Jewish, I would hope that every person in this country wants to see the misery of never-ending war and conflict ended in the Middle East. It's a difficult issue and good people have tried to deal with it for years."
Sanders said the United States must play a role in supporting Israel while not ignoring the challenges of the Palestinian people.
"Of course we are going to support Israel, but you cannot ignore the needs of the Palestinian people in Gaza right now: poverty, unemployment, their community has been decimated," Sanders said. "You can't ignore that fact. And you can't just be only concerned about Israel's needs. You have to be concerned about the needs of all of the people of the region."