That controversial phrasing has been interpreted by the Anti-Defamation League to convey an interest in eliminating the state of Israel.
"Rashida Tlaib RT's [retweets] out the same message that got Marc Lamont Hill canned from CNN," tweeted the account for StopAntiSemitism.org.
"From the River to the Sea, Palestine will be Free - code for eradicating the State of Israel and its millions of Jews. Reminder - this is a sitting U.S. Congresswoman."
The group was referring to a former CNN commentator who was fired from the network after a speech he gave at the United Nations in 2018. At the time, Hill denied calling for Israel's destruction.
"My reference to 'river to the sea' was not a call to destroy anything or anyone," he tweeted.
"It was a call for justice, both in Israel and in the West Bank/Gaza. The speech very clearly and specifically said those things. No amount of debate will change what I actually said or what I meant."
Tlaib has faced criticism over her support for Palestinians and the way she talked about Jews.
Tlaib was criticized by House Republicans last year after describing the "calm feeling" she experienced when thinking about the Holocaust. However, the congresswoman said her critics were policing and "twisting" her words and defended the comments she made.
The Michigan congresswoman also made headlines when she sought a humanitarian visit to her grandmother after the Israeli government rejected her and Rep. Ilhan Omar's, D-Minn., request to enter the Jewish state. Citing the two's itinerary, Israel claimed that their visit was intended to promote boycotts against the nation.
Tlaib later requested the humanitarian visit through a letter that contained a promise not to promote boycotts. But the Michigan Democrat reversed course after Israel accepted her request, claiming she would have to go under "oppressive conditions."
On Sunday, Tlaib referenced her grandmother, or "sity," in a tweet with the photo called out by StopAntiSemitism.org.
"Thinking of my sity Muftieh and family in Palestine today. From Detroit to Gaza, we will always fight against oppression and inequality," she said.
Tlaib's office did not immediately respond to Fox News' request for comment. Earlier this month, she came under fire for participating in a panel on "dismantling anti-Semitism."