WASHINGTON, Dec 21, 2012 (AFP) - US President Barack Obama will nominate Senator John Kerry, a veteran foreign policy hand and former presidential candidate, as his next secretary of state on Friday, a US official told AFP.

An official announcement on the appointment of the Vietnam war veteran who will succeed Hillary Clinton as the top US diplomat was expected later on Friday, the official said.

Kerry, the head of the Senate Foreign Relations Committee is expected to win easy confirmation from his colleagues in the chamber, and is a well known figure on the world stage.

The Massachusetts senator has rehabilitated his career since narrowly losing the 2004 presidential race to president George W. Bush, after a campaign that included savage attacks on his career as a swift boat commander in Vietnam.

Susan Rice withdrew nomination 

Kerry's appointment was seen as almost a certainty after UN ambassador Susan Rice pulled out of the running for the job, over Republican attacks on her role in the aftermath of the assault on the US consulate in Benghazi.

The Massachusetts senator played an important role in Obama's political career, notably by picking him to give the keynote speech in the 2004 Democratic convention, at which the then unknown Illinois lawmaker burst onto the political scene.

Kerry also played Republican presidential candidate Mitt Romney in mock debates staged by the president's team ahead of Obama's successful re-election effort in November.

Clinton has said she wished to step down after Obama begins his second term in office next month and her replacement is confirmed.

Mr. Kerry gave a speech during the US Presidential campaign, attacking the policies of rival Mitt Romney: