In his new role, Kirby will coordinate interagency efforts to clarify US policy and serve as the White House's senior spokesman on issues related to the core area, according to an official release from the US administration.

"John Kirby is uniquely qualified for this position, and I look forward to bringing his experience and expertise to the White House," Biden said.

Kirby in his new post will be subordinate to US national security adviser Jake Sullivan.

Earlier, the US Senate unanimously approved the candidacy of Bridget Brink for the post of US Ambassador to Ukraine.

Jen Psaki resigned as White House press secretary on May 13.

Her post was taken by Karine Jean-Pierre.