SAO PAULO - President Dilma Rousseff will make the first formal state visit by a Brazilian leader to the United States in nearly two decades, a diplomatic breakthrough for an emerging power that has clashed with Washington but is hungry for closer ties and recognition of its growing prestige.

The trip will occur later this year, likely in October, officials told Reuters on condition of anonymity because the White House has not yet announced the visit. A White House spokeswoman declined comment.

A state visit, which includes formalities such as a black-tie dinner and a military ceremony upon arrival, is usually reserved for Washington's closest strategic partners.

"It's great news, long overdue," said Paulo Sotero, director of the Brazil Institute at the Wilson Center, a think-tank in Washington. "It shows that the United States really values the relationship, which is what Brazil most wants to hear."

The upgrade in diplomatic ties is likely to rekindle hopes for a long-sought treaty to avoid double taxation on Brazilian and US businesses, as well as the chance for greater commerce between the two largest economies in the Americas.

Bilateral trade totaled about $59 billion last year, but Brazil's economy remains relatively closed to imports and its 200 million-strong population is seen as a big potential growth market for US companies.

The red-carpet reception also will be a political victory for Rousseff, a left-leaning but pragmatic leader who has sought closer relations with the United States but felt snubbed when President Barack Obama did not host a more elaborate welcome during a White House visit in April 2012.

Relations have been cordial, but marked by disagreements.

Latin America's biggest country has been frustrated by a perceived lack of support from Washington as it seeks a permanent seat on the United Nations Security Council and other recognition of its rising influence following an economic boom over the past decade.

PROBLEMS UNDER LULA  

Rousseff's predecessor, Luiz Inacio Lula da Silva, angered Washington by blocking hemispheric trade talks and trying to broker a deal to end the global standoff over Iran's nuclear program in 2010, the final year of his presidency.

Rousseff, by contrast, has mostly avoided dealing with Iran, more strongly emphasized human rights in Brazil's foreign relations and also taken a relative distance from Venezuela, Washington's loudest antagonist in Latin America.

Sotero said Obama's visit to Brasilia in March 2011 marked the beginning of a "reset" in relations.

"For a while there was really very little dialogue," Sotero said. "This (state visit) gives me more optimism that we've moved on from that."

It's unclear whether Rousseff will be a more enthusiastic partner on trade than Lula.

Brazil's recent economic slowdown and strained ties with major trading partner Argentina have prompted speculation that Rousseff might be willing to push for greater commercial ties with the United States or European Union.

However, she has also implemented targeted tariff increases to protect Brazilian industries from what she calls a "currency war" being waged by the United States and other rich countries to devalue their currencies for trade purposes.    

The last Brazilian president to make a state visit to the United States was Fernando Henrique Cardoso, in 1995.