US President Barack Obama named Susan Rice as his new national security adviser on Wednesday, defying Republican anger over her role following the terrorist attack in Benghazi and increasing the White House's control over foreign policy.

Rice, currently US ambassador to the United Nations and an Obama confidante, will take over from Thomas Donilon in July. Donilon, a key figure in US-China policy who masterminded Obama's diplomatic "pivot" to Asia, has resigned, but will attend the summit between Obama and President Xi Jinping in California on Friday and Saturday.

Rice's appointment, along with the nomination of Samantha Power as her successor at the UN, signals a shift by Obama toward advisers who favor more robust US intervention overseas and confirms his penchant for promoting from within his tight political inner circle, Western media said.

Rice has been a strong advocate at the UN for stricter sanctions against Iran and the Democratic People's Republic of Korea, and also pushed for the US and allies to use military force to help Libyan rebels oust Muammar Gadhafi in 2011.

Observers said although Rice is not as experienced on China-related issues as Donilon, she will catch up quickly to address important Sino-US relations and global affairs with major powers like China.

In a ceremony at the White House Rose Garden on Wednesday, Obama said Rice "exemplifies the finest tradition of US diplomacy and leadership", and described her as "passionate and pragmatic".

Obama once vigorously defended Rice after she was accused of misleading the public over the deadly attack against the US consulate in Benghazi, Libya, last year. Later, Rice was forced to pull out of the running to be secretary of state.

In her remarks, Rice did not mention the attack or the Republican criticism. She said she looked forward to working with "our country's most experienced leaders from both parties".

Donilon, who recently traveled to Beijing to prepare Xi's visit to the US, was praised by Obama as one of the most effective national security advisers in US history, and instrumental in renewing US leadership in the Asia-Pacific region.

"He has worked tirelessly to forge a constructive relationship with China that advances our interest and our values," Obama said.

'Smart diplomat'

Orville Schell, director of the Center on US-China Relations at the Asia Society in New York, described the 48-year-old Rice as a smart and experienced diplomat, doubting that Rice's limited direct experience in China-related matters would be problematic.

"She is a fast study," said Schell, adding that US Vice-President Joe Biden's close relationship with Xi is also helpful.

Bonnie Glaser, a senior adviser for Asia at the Center for Strategic and International Studies, said Donilon also had little China experience when he took the same post, but he gained experience on the job.

In addition, Rice gained a great deal of experience working with China at the UN Security Council on three important issues: the DPRK, Syria and Iran, Glaser said.

"Over time, since the president attaches a great deal of importance to the relationship with China and is committed to the rebalance to Asia, Dr Rice will be even more involved in the US-China relationship."

Zbigniew Brzezinski, former national security adviser for US president Jimmy Carter, recently criticized Rice for lacking diplomacy when she publicly called Russia and China "disgusting and shameful" after they vetoed a UN Security Council resolution on Syria last July.

Zhu Zhiqun, a professor of political science and international relations at Bucknell University in Pennsylvania, said Rice "will likely not be an agenda-setter, but will work closely with (Secretary of State John) Kerry and other members of Obama's foreign policy team".