A Florida Republican with national party ties has been condemned after becoming the latest political opponent of the Minnesota congresswoman Ilhan Omar to suggest that the Minnesota representative be put to death.

A fundraising letter sent by George Buck, a Republican running for Congress, suggests that Omar, a Democrat, be executed for treason. “We should hang these traitors where they stand,” the email reads.

According to the Tampa Bay Times, Buck initially blamed the email on an errant staff member before seemingly backtracking and sending the newspaper a statement that referenced the death penalty for treason.

“Anyone who commits treason against the United States should be tried to the full extent of the law,” said Buck, who is a member of the Young Guns program run by the National Republican Congressional Committee (NRCC).

On Wednesday the NRCC and Kevin McCarthy, Republican House minority leader, removed Buck from the program in the wake of his comments.

Buck is the second Republican to reference the hanging of Omar, a Somali-born Muslim, in the past week. A campaign account for Danielle Stella, a pro-Trump Republican candidate for Congress, was banned from Twitter after suggesting Omar be hanged, along with a depiction of a stick figure hanging from the gallows.

Both Buck and Stella have based their accusations of treason on an unverified report that Omar is an asset of Qatar who has passed sensitive information on to Iran. There has been no evidence put forward to support this theory and has not been backed by any US government assessment.

Omar is a frequent critic of Donald Trump, as well as the human rights records of both Israel and Saudi Arabia. Trump has repeatedly accused his critics of being guilty of treason and said Omar and other political opponents in Congress who are women of colour should be “sent back” to the “crime infested places from which they came” despite their either being born in the US or gaining citizenship and now holding national office.

“The fact that those who make these violent threats very publicly without hesitation reaffirms how much white supremacy has spread within the @NRCC,” tweeted Rashida Tlaib, a Michigan Democrat and Omar ally who has also been targeted by Trump. “They are raising money on a call to hang a Black Muslim member of Congress and too many are silent.”

The fact that those who make these violent threats very publicly without hesitation reaffirms just how much white supremacy has spread within the @NRCC. They are raising money on a call to hang a Black Muslim member of Congress and too many are silent. @IlhanMN https://t.co/VR92QvWh2z — Rashida Tlaib (@RashidaTlaib) December 4, 2019

Steve Scalise, the House Republican whip, also criticised Buck. “There’s no place for inciting violence in politics,” Scalise said in a statement. “Instead of doubling down on these disgraceful comments, the candidate ought to apologize unequivocally and denounce these unacceptable statements.”

Buck is one of several Republicans vying to take Florida’s 13th congressional district, which is centered on the city of St Petersburg. The incumbent in Charlie Crist, a Democrat and former Florida governor.