US Representative Cori Bush, a fierce critic of Israel's war in Gaza, has lost her Democratic congressional primary, according to results called by US media.
Bush, seen as one of the most prominent progressives in Congress, was defeated by Wesley Bell, a county prosecutor who enjoyed the backing of the influential pro-Israel lobby group American Israel Public Affairs Committee (AIPAC).
"We will stand up for what is right, no matter the cost," the Missouri congresswoman, who was voted into the House in 2020, said in a concession speech on Tuesday night posted on her account on social media platform X.
"I just hope he (Bell) actually takes time to learn about our Palestinian, our Arab and Muslim community... and that he sees the beauty in what we have created," she said .
Bush introduced a resolution in Congress calling for a ceasefire in Gaza just weeks after the start of the war triggered by the October 7 Hamas attack on Israel.
She boycotted Israeli Prime Minister Benjamin Netanyahu's address to a joint sitting of Congress last month, saying attending would be celebrating a "war criminal" at the forefront of a "genocide".
A pastor and nurse, Bush became a Black Lives Matter activist and led protests after the shooting death of Michael Brown in Ferguson, Missouri, in 2014.