Two far-right members of Congress whose threatening behavior prompted their removal from committees when Democrats controlled the US House were given assignments on Tuesday by the new Republican speaker, Kevin McCarthy.

Marjorie Taylor Greene of Georgia will sit on the House homeland security committee. Paul Gosar of Arizona was named to the natural resources panel.

Democrats removed Greene from committees in February 2021, citing incendiary behavior including advocating the assassination of opponents and voicing support for QAnon and other conspiracy theories, including bizarre claims about 9/11 and the Parkland school shooting.

Eleven Republicans supported Greene’s removal but despite being condemned by party leaders for speaking at a white supremacist conference last February, the Georgia congresswoman has since become close to McCarthy.

Earlier this month, Greene refused to join the far-right rebellion which dragged McCarthy through 15 rounds of voting before he was confirmed as speaker.

Greene, who recently said the January 6 attack on the US Capitol would have succeeded had she organised it, will now sit on the homeland security committee.

That panel is set to spearhead Republican attacks, possibly including impeachment, against Alejandro Mayorkas, Joe Biden’s secretary of homeland security, over immigration policy and border security.

On Tuesday, Greene tweeted: “It is time to restore dignity to the people, Border Patrol, ICE [Immigration and Customs Enforcement], and the families who have lost a loved one to the cartel’s fentanyl murders and illegal alien crime.

“I serve the American people and no one else. As far as I’m concerned American dignity is the only one that matters.”

Gosar, who attended the same white supremacist conference as Greene, was censured and removed from committees in November 2021, after tweeting an anime-style video which showed him striking the New York progressive Alexandria Ocasio-Cortez with a sword and also menacing Biden. Two Republicans supported the move.

Earlier this month, early in the run of votes by which McCarthy became speaker, Gosar and Ocasio-Cortez were filmed talking to each other in the House chamber.

Ocasio-Cortez told MSNBC: “In chaos, anything is possible, especially in this era.”