India, March 6 -- President Donald Trump removed Kristi Noem as Homeland Security secretary and announced he would replace her with Oklahoma Senator Markwayne Mullin.

"I am pleased to announce that the Highly Respected United States Senator from the Great State of Oklahoma, Markwayne Mullin, will become the United States Secretary of Homeland Security (DHS)," Trump posted on social media. "I thank Kristi for her service at 'Homeland.'"

Trump said the move would become effective on March 31.

He also announced that Kristi Noem would take a role as Special Envoy for The Shield of the Americas," a new security initiative that he said would focus on the Western Hemisphere.

Markwayne Mullin is known for his strongly conservative positions o...