American officials are warning that attacks on minority Muslims and foreign aid groups in Myanmar are threatening the nascent thaw in relations between Washington and this former pariah state.

The Obama administration counts Myanmar's transition from military rule as a major foreign policy success for the president and his former secretary of state, Hillary Rodham Clinton. For Myanmar leaders, normalizing relations with the U.S. government was key to ending their dependency on China.

But allegations, disputed by the Myanmar government, that dozens of Rohingya Muslims were massacred by mobs of Buddhists in western Rakhine state in January have outraged human rights groups and members of Congress.

Adding to the concern, radical Rakhine Buddhists attacked the offices and homes of foreign aid workers in the state in March. The Buddhists accuse the aid organizations of providing disproportionate assistance to the Muslims.

Daniel Russel, the assistant U.S. secretary of state for East Asian and Pacific affairs, visited Myanmar last week to push President Thein Sein and other officials to allow the return of aid groups that have been forced to leave the area.

"The fact that we have a stake in the success of the government and the reform efforts doesn't mean that we pull punches," Russel told foreign journalists in Yangon, the commercial capital of Myanmar. "The crux of my message was: The whole world is watching."

The U.S. and other Western governments have embraced the reformist government that took over here in 2011, following decades of military dictatorship. Long-standing economic sanctions have largely been suspended, and economic aid has flowed.

Rakhine

But the picture on the ground is complex. In Myanmar, also known as Burma, a growing measure of democracy and economic reform co-exist with a virulent strain of Buddhist nationalism.

"'There's an inability in London and Washington to entertain two contradictory narratives about this country," said Richard Horsey, a Yangon-based analyst and former International Labor Organization representative to Myanmar. "That's one reason why Rakhine is so dangerous and so potentially corrosive to the U.S.-Myanmar strategic relationship."

The risk, Horsey says, is "making the relationship hostage to the events in Rakhine, which the central government does not have the ability to fully control."

Rakhine state, formerly called Arakan, was a kingdom in its own right until it was conquered by the Burmese in the late 18th century. People from the predominantly Buddhist Rakhine ethnic group are a majority in the state.

While many Rohingya have lived within Myanmar's borders for generations, the military government in 1982 classified most of them as illegal immigrants from neighboring Bangladesh.

United Nations agencies and the U.S. Embassy in Yangon have been vocal in pushing for investigations and measures to end violence and discrimination against the largely impoverished Rohingya and other Muslims.

But Myanmar's leaders present Rakhine as an internal issue with little bearing on their reform efforts. And with national elections approaching in 2015, politicians appear reluctant to alienate Rakhine leaders, particularly since many in central Myanmar share a paranoia about the "Islamization" of the largely Buddhist country.

"While the government probably knows what it needs to do, and while it does place importance on its nascent good relations with the U.S., it is now caught in a fix that democratic institutions cannot solve," says Moe Thuzar, a former Myanmar diplomat who is now a fellow at the Institute of Southeast Asian Studies in Singapore. "Remember, 2015 is just months away, and everyone is thinking in terms of votes."

The Associated Press and other news agencies reported in January that a massacre of Rohingya Muslims had occurred in northern Rakhine state that month. U.N. human rights officials subsequently said they had received credible information that 48 Rohingya men, women and children had been slain in the village of Du Chee Yar Tan, along with a police sergeant. The government has flatly denied reports of the Rohingya killings.

State authorities forced the aid group Medecins Sans Frontieres, or Doctors Without Borders, to leave the state in February after it said it had treated some victims of the attacks. The group's departure has raised concerns of a humanitarian crisis, because state-level laws restrict Muslim access to basic health care.

Then, in late March, a mob of Rakhine Buddhists attacked the offices and homes of foreign aid workers in the state. They were upset by the government's decision to allow people to identify themselves as Rohingya in Myanmar's first national census in 31 years. The government subsequently abandoned that practice.

Myanmar's government has made arrests in those attacks, and pledged last week to protect international aid groups. But according to state media, Army Maj. Gen. Maung Maung Ohn, who is leading an investigatory commission, said that the foreign groups need to be more sensitive to the concerns of Rakhine Buddhists.

Oo Hla Saw, the general secretary of the Rakhine National Development Party, one of the two major Rakhine political parties, insisted in an interview that most Rakhine people deplore mob violence. But he said that international groups and American leaders "don't understand the realities of the Rakhine situation. In any issue, they side with the Rohingya radicals."

Rohingya

In 2012, clashes between Buddhists and Rohingya killed scores of people and left thousands in internal displacement camps. New York-based Human Rights Watch accused the government of complicity in the violence against the Muslims. The group's former director in Washington, Tom Malinowski, was confirmed by the U.S. Senate as assistant secretary of state for democracy, human rights and labor this month.

The U.S. government's concerns about Myanmar also include recent curbs on press freedom and a lack of progress on revising the constitution. But the Rakhine turmoil, in particular, has provided a "told-you-so" moment for some human rights groups and American lawmakers wary about the extent of reform in Myanmar.

Rep. Edward R. Royce, R-Calif., chairman of the House Foreign Affairs Committee, said at a hearing last month that "the government of (Myanmar) cannot claim progress toward meeting its reform goals if it does not improve the treatment of Rohingya Muslims and other minority groups." He urged the State Department "to take off the rose-colored glasses."

Supporters of continued engagement worry that a lack of action by Myanmar's central government could anger Congress and undermine economic aid and government ties.

Still, nobody is talking about a return to the days of sanctions and estrangement.

Russel said the U.S. government is interested in Myanmar's role, as the current chair of the Association of Southeast Asian Nations (ASEAN), in helping mediate territorial disputes in the South China Sea. President Barack Obama is expected to visit Myanmar in November, two years after his historic arrival in Yangon for a regional summit.

The immediate challenge for U.S. officials is how to press for action on the Rohingya issue without backing the Myanmar government into a corner, analysts say.

"The (Myanmar people) need a combination of practical help and moral support on the one hand, and cleared-eyed and clear-spoken feedback on the other," Russel said. "There is no complacency in our approach to the challenges here in (Myanmar)." - By Joseph J. Schatz