A former senior U.S. defense official touted as the most likely candidate to succeed Chuck Hagel as Pentagon chief has taken herself out of the running, a source familiar with the situation told Agence France Presse on Tuesday.

Michele Flournoy, 53, was widely considered the frontrunner for the post of defense secretary and if confirmed would have been the first woman to hold the position. 

Fury mounted in the U.S. town of Ferguson on Tuesday as the family of a slain black teenager denounced the "broken" justice system that failed to indict the white policeman who shot him.

Lawyers for the family of Michael Brown, backed by civil rights leaders, denounced the prosecutor whose grand jury hearing found that the officer had killed the 18-year-old in self-defense.

President Barack Obama announced the departure of U.S. Defense Secretary Chuck Hagel on Monday, with the White House under fire over perceived fumbling in its response to the Islamic State threat.

The former Republican senator, who has been in the job for less than two years, was chosen to oversee a shift to a peacetime military with smaller defense budgets, but found the United States at war again.

U.S. President Barack Obama warns that "significant gaps" remain with Iran over its disputed nuclear program, as a deadline for a deal looms large.

Iran and world powers, including Washington, engaged Sunday in a diplomatic blitz less than 36 hours before the cutoff time for an agreement, with officials on both sides insisting they were still pulling out all the stops in the Vienna talks.

Barack Obama says voters in the United States are going to want "that new car smell" when the 2016 presidential campaign comes along to choose his successor.

Obama's former secretary of state Hillary Clinton is strongly fancied to run on the Democratic ticket for the White House, although she has repeatedly refused to confirm she wants to do so.

A Saudi Arabian inmate at the U.S. prison in Guantanamo Bay, Cuba was repatriated Saturday, leaving 142 prisoners still at the jail President Barack Obama has pledged to close, the Pentagon said.

Mohammed al-Zahrani is the latest of seven prisoners freed from the controversial jail in the past three weeks, and his release comes just days after authorities transferred five inmates to Georgia and Slovakia. 

U.S. President Barack Obama telephoned Pakistani Prime Minister Nawaz Sharif to discuss the "evolving situation" in the region, the Pakistani foreign ministry said.

"Prime Minister Nawaz Sharif expressed satisfaction at the direction of Pakistan-U.S. relations which were on an upward trajectory" and "President Obama noted Pakistan-U.S. relations were strong and robust" during their conversation Friday evening the ministry said in a statement.

Barack Obama has extended the combat role for U.S. troops in Afghanistan for another year, in a classified order he signed in recent weeks, the New York Times reported Friday.

Previously, the president had said U.S.-led NATO combat operations would finish at the end of this year.

U.S. President Barack Obama will travel to India in January for its Republic Day celebrations, and talks with Prime Minister Narendra Modi, the White House said Friday.

"The president will meet with the prime minister and Indian officials to strengthen and expand the U.S.-India strategic partnership," White House press secretary Josh Earnest said.

U.S. President Barack Obama congratulated the Lebanese people on Friday on the occasion of Lebanon's 71st Independence Day, lamenting on the anniversary the current vacuum in the presidency.

He said in a message to Lebanon: “As a friend of the Lebanese people, the United States regrets this anniversary day passes without an elected president of the Lebanese Republic, an important but missing symbol of the unity of the nation and a key factor in promoting Lebanese sovereignty and stability.”