WASHINGTON » With tensions rising over China’s recent crackdown on dissent, the Obama administration is about to lose three of its most prominent players on China policy — a shakeup that could reinforce its efforts to cultivate other Asian countries to counterbalance an increasingly assertive Beijing.

Jeffrey A. Bader, President Barack Obama’s top China adviser, is leaving the White House, senior officials said Friday. James B. Steinberg, a deputy secretary of state who also focused heavily on China, has announced plans to take a job in academia, while the U.S. ambassador to China, Jon M. Huntsman Jr., will step down at the end of April to explore a bid for the Republican presidential nomination.

Taken together, the departures could alter the tone of the administration’s approach to China, one of its most vital but difficult relationships. Bader will be replaced at the National Security Council by his deputy, Daniel R. Russel, a Japan expert. Steinberg’s exit raises the profile of Kurt M. Campbell, the assistant secretary for East Asian affairs, who also has worked intensively on Japan.

While Russel and Campbell have traveled to Beijing regularly in the past two years, their Japan pedigrees serve as a reminder to China that the United States has other old friends in the region. Since Obama took office, the United States has worked to shore up alliances with Japan and South Korea and to deepen ties with Indonesia, Vietnam and other neighbors that worry about China’s regional ambitions.

White House officials played down any message in the changes, noting that China policy is coordinated by the national security adviser, Thomas E. Donilon, and that Obama has met President Hu Jintao eight times — an unusual amount of contact that demonstrates the importance the administration attaches to China.

"We’re going to have challenges going forward," Donilon said of China in an interview Thursday. "But we work from a better base, and more important, we work from a stronger base in the region."

Among those challenges is China’s recent detention of dozens of lawyers, journalists, artists and human-rights activists, which U.S. officials said appeared to be aimed at preventing the popular uprisings in the Arab world from spreading to China. The State Department cited the arrests in its annual human-rights report, issued Friday, and Secretary of State Hillary Rodham Clinton bluntly criticized China.

On Wednesday, Huntsman used a farewell speech in China to deliver a rebuke of Chinese authorities for detaining Ai Weiwei, a prominent Beijing artist, as he was trying to board a flight to Hong Kong on Sunday. He also said China had wrongly jailed an American geologist, Xue Feng, who was accused of stealing state secrets while researching the Chinese oil industry.

Huntsman has been in an awkward spot, still serving as Obama’s emissary even though there were indications that he might challenge him for the presidency in 2012. But administration officials said his remarks faithfully echoed the administration’s criticism.

Huntsman’s successor will be Gary Locke, the former governor of Washington who is now commerce secretary. A senior official predicted that Locke would be warmly received in China because of his status as one of the highest-ranking Chinese-Americans in the government, as well as his record in Washington state, where he worked on trade ties with China for local exporters like Boeing.

Trade friction between Beijing and Washington has eased a bit in recent weeks, with the upswing in the American economy and a modest rise in the value of China’s currency. In February, the Treasury Department declined again, in a twice-yearly report, to cite China for manipulating its currency, though it said the currency, the renminbi, remained "substantially undervalued" compared with the dollar.

The White House pointed to signs of improvement, including China’s decision not to veto a U.N. resolution authorizing military action in Libya as well as its support for sanctions against Iran. Chinese officials are toning down maritime claims in the South China Sea, an issue that flared up last year when Clinton said the United States wanted to help resolve disputes between China and its neighbors.

After a fraught period between the two countries, over disputes ranging from climate change to North Korea, Hu had a smooth state visit in January. It had been exhaustively planned by Donilon and Bader, who traveled to Beijing last fall with Obama’s former top economic adviser, Lawrence H. Summers. It was a trip that cemented Donilon as the key administration figure on China.

Donilon has kept up his contacts with Chinese officials, but he is not a China hand by background or education.

With Bader’s departure for the Brookings Institution, the administration is losing a Chinese-speaking official whose involvement with China goes back to the normalization of relations in 1979. He also came up with the idea of appointing Huntsman, then the governor of Utah who had been a Mormon missionary in Taiwan.

Russel, Bader’s replacement, speaks Japanese and was consul general in Osaka, Japan, from 2005 to 2008. Noting that he worked at the United Nations and in Europe, Russel said that someone’s focus cannot be extrapolated from their background, "because their focus is what the president’s focus is." For all his history with China, Bader was the architect of a policy that has stressed tightening ties with all the countries around it. He said Russel’s regional focus made him the right choice to carry that forward.