Protesters burning the Israeli flag outside the Democratic National Convention. Photo: Twitter/United With Israel.

A former star player for the Boston Red Sox expressed dismay on Wednesday over the burning of Israeli flags outside the Democratic National Convention (DNC) in Philadelphia.

“Sad to see the hatred that still exists for Israel and Jews across the world,” Kevin Youkilis tweeted, along with the hashtags “StopTheHate” and “NeverAgain.”

Youkilis’ Twitter followers responded in kind, with comments such as, “so true and so sad,” “Amen” and “That is absolutely nauseating to see, especially in my hometown!” One social media user even thanked the former professional baseball player for “speaking up.”

As The Algemeiner reported, eyewitnesses at the Wells Fargo Center, where the DNC is being held, said protesters were burning Israeli and American flags on Tuesday night, while chanting “Black Lives Matter” and “Long Live Palestine.” Activists also waved signs that read, “From the river to the sea, Palestine must be free,” a slogan calling for the elimination of the state of Israel.

The National Jewish Democratic Council condemned the flag-burning on Twitter, calling it “Disgusting and totally reprehensible. These protesters aren’t only wrong, but are fundamentally anti-progressive.”

Meanwhile, inside the convention center, Palestinian flags were prominently displayed and attendees were seen holding up signs that read, “I support Palestinian human rights.”

The DNC started on Monday and continues until Thursday.