Vermont Sen. Bernie Sanders called on Israel to end its decades-long occupation of Palestinian territories in a speech to a liberal Jewish organization in Washington on Monday.

Sanders spoke for more than a half hour at an annual event organized by J Street, a group that is dedicated to promoting dialogue between Washington, Israelis and Arabs in the Middle East. Sanders asserted Israel's right to exist and the usefulness of a strong relationship between Washington and Tel Aviv, but condemned Israel's treatment of Palestinians as well as its "50-year occupation" of Palestinian land.

"There is no question that we should be and will be Israel’s strong friend and ally in the years to come," Sanders said. "At the same time, we must recognize that Israel’s continued occupation of Palestinian territories and its daily restrictions on the political and civil liberties of the Palestinian people runs contrary to fundamental American values."

Sanders, who is Jewish and spent time in Israel during his youth, said it was necessary to establish a "Democratic homeland for the Jewish people." However, he referred to a "trail of tears" experienced by Palestinians expelled from their homeland during Israel's foundation in 1948 and annexation of more neighboring territories in 1967. He compared Israel's conquest of Palestinians, from which "over 700,000 people were made refugees," to the U.S.' treatment of Native Americans and called for both Israelis and Palestinians to reject extremism and to engage one another in dialogue.

The influential socialist lawmaker, one of only two independents in Congress, has emerged as a symbol of anti-establishment fervor within the left-wing. While not a member of the Democratic Party, he unsuccessfully ran for that party's nomination in last year's presidential election, ultimately losing to centrist candidate former Secretary of State Hillary Clinton. Since Clinton's surprise defeat to Republican President Donald Trump in November, Democrats have repeatedly looked to Sanders to rally his extensive list of progressive supporters, but have been reluctant to grant him or his allies positions in the party. Sanders' nomination for Democratic National Committee head, Rep. Keith Ellison, was turned down Saturday in favor of centrist labor leader Tom Perez.

Sanders has previously stated his support for the Iran nuclear deal, which was vehemently opposed by conservatives in the U.S. and Israel. However, his criticism Monday of both President Donald Trump and Israeli Prime Minister Benjamin Netanyahu's suggestion that the U.S. may abandon its two-state solution approach to the regional peace process appeared to be the lawmaker's most progressive stance on Middle East foreign policy yet. Sanders backed Obama's controversial decision to abstain from vetoing a U.N. Security Council resolution in December condemning Israel's policy of building settlements on Palestinian territory.

"To oppose the policies of a right-wing government in Israel does not make one anti-Israel or anti-Semitic," Sanders said. "We can oppose the policies of President Trump without being anti-American. We can oppose the policies of Netanyahu without being anti-Israel. We can oppose the policies of Islamic extremism without being anti-Muslim."