Omar, a member of the progressive "Squad," posted a tweet that said that the U.S. needs to "have the same level of accountability and justice for all victims of crimes against humanity."
The Minnesota Democrat then said America and Israel have committed "unthinkable atrocities" like those committed by the terrorist groups.
"We have seen unthinkable atrocities committed by the U.S., Hamas, Israel, Afghanistan, and the Taliban," wrote Omar. "I asked [Secretary of State Antony Blinken] where people are supposed to go for justice."
The post also included a video of the congresswoman challenging Blinken during the House Foreign Affairs Committee's Monday hearing on the State Department's budget request and foreign policy strategy.
While Omar's tweet directly arranged America with terrorist organizations, her line of questioning in the video did not. In her questioning of Blinken, Omar indicated that Israel, Hamas, the government of Afghanistan and the Taliban have all committed war crimes.
The Minnesota congresswoman is no stranger to disagreement. Late last month, Omar accused Israel of committing "war crimes" following days of conflict between Israel and Hamas that saw thousands of missiles fired indiscriminately at Jerusalem and Tel Aviv.
"We should all be grateful that a ceasefire will prevent more civilians and children from being killed," Omar tweeted in May. "But now what? We need accountability for every war crime committed."
"And we need to stop underwriting crimes against humanity while doing nothing to end the occupation," she continued.
Facebook refused to remove an attack ad associating Democratic Rep. Ilhan Omar with Hamas, even after her aides said similar claims had resulted in death threats to the lawmaker in the past.
The ad was produced by the American Israel Public Affairs Committee, the pro-Israel lobbying group, and showed the face of the Minnesota lawmaker, who is Muslim, superimposed onto rockets fired by Gaza militants toward Israel.
"When Israel targets Hamas, Rep. Omar calls it an act of terrorism," the caption said. The ad is still live on Facebook.
The ad appeared to be based on a tweet by Omar that said Israel's killing of Palestinian civilians in Gaza constituted an act of terrorism. Israel has said it takes precautions to narrowly target Hamas and other militant targets in Gaza, but many civilians have been reported killed there by Israeli airstrikes, including dozens of children.