Japan’s top trade negotiator said the Trump administration has agreed to correct an “extremely regrettable” blunder in the execution of its trade agreement with the country, according to The New York Times.

Japanese officials believed they had secured a deal in negotiations in July, that would set a standard tariff rate of 15% percent for all of its products exported to the U.S., in return for pledges to invest hundreds of billions of dollars in the U.S. and open its market to more American goods. In a July 31 executive order, the Trump administration outlined a similar scheme for the European Union.

But Japan was instead assigned a “stacked” tariff on top of existing ones, that raised tariffs on items such as its beef exports to the U.S. from 26.4 percent to 41.4 percent.

On August 7, Japan’s chief trade negotiator, Ryosei Akazawa, said he had secured a promise from the Trump administration to fix the error. Local media had earlier reported that the U.S. was not planning to revise the presidential order, citing unidentified White House officials.

The Times says this latest development is another example of how a deal with no publicly disclosed written joint agreement — assembled quickly just days before higher threatened tariffs were set to take effect — is causing confusion and growing tension between the U.S. and one of its top allies and trading partners.