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President Dilma Rousseff of Brazil has cancelled a planned state visit to Washington in October over reports that the United States spied on her personal communications and those of other Brazilians.

The decision, confirmed by the White House, is a major and very rare snub of a high-pageantry Washington celebration to honor a close ally. It came after President Obama and national security adviser Susan Rice had invested significant time and personal attention to try to salvage the trip.

In a statement, Rousseff said the alleged spying was "incompatible with the democratic coexistence between friendly countries" and that her concerns about U.S. activities have not been sufficiently addressed.

"Given the absence of a timely review of those practices with corresponding explanations and commitment to cease the interception activities, the conditions for a visit on the previously agreed-upon date are not present," she said.

Obama met one-on-one with Rousseff on the sidelines of the G-20 summit earlier this month to discuss the U.S. surveillance operation, which was first revealed in leaks of NSA documents by Edward Snowden. He spoke Monday by phone with Rousseff for a reported 20 minutes about her concerns. Rice met at the White House with the Brazilian foreign minister last week.

The White House said the visit was merely "postponed" until a later "mutually agreed" date.

It's not clear if or how soon the Obama administration may resolve Rousseff's concerns. In a statement, White House spokesman Jay Carney said the president "understands and regrets the concerns" generated by the NSA disclosures but stopped short of expressing regret for the activity itself.

The administration has neither publicly confirmed nor denied that it has spied on Rousseff.

During their phone call Monday, when both leaders agreed to scrap the state visit, Obama "made clear that he is committed to working together with President Rousseff and her government in diplomatic channels to move beyond this issue as a source of tension in our bilateral relationship," Carney said in the statement.

The state visit, which would have been the first for Brazil since 1995, was formally announced May 29. The state dinner was set for Oct. 23. The office of first lady Michelle Obama said that invitations to the dinner had not yet been sent out.

This post has been updated.