OTTAWA — Japanese officials say they believed they were also negotiating with Canada and Mexico when they struck a controversial side agreement with the United States on automobiles last year during the Trans-Pacific Partnership talks.

They discussed that agreement with U.S., which angered Canada and Mexico, in a briefing ahead of a Friday meeting between Foreign Affairs Minister Stephane Dion and his Japanese counterpart, Fumio Kishida.

The Japan-U.S. deal on rules of origin in the auto sector would have allowed a higher percentage of Japanese parts in cars in North America's highly integrated industry. The fallout stalled completion of the 12-country Pacific Rim deal by at least two months.

The Japanese officials say they were surprised to learn that they had negotiated a deal with only the United States.

"We thought that the U.S. represented Canada and Mexico."

Mexico's former ambassador to Canada has said the side deal angered the Canadians and Mexicans and nearly drove the two countries from the bargaining table.

But the Japanese officials, who briefed journalists on the condition they not be named, said their government didn't think they were doing anything to snub Canada and Mexico.

"We thought that the U.S. represented Canada and Mexico," said one.

They did not explain why they thought the United States was negotiating on behalf of Canada and the Mexico. "We were very surprised'' to learn "Canada had not been consulted by the U.S.,'' said one official.

Kishida, during a joint news conference with Dion, deflected a question on the issue.

"There was very tough negotiations that were conducted," he said through a translator.

"They have reached a conclusion that everybody's comfortable with."

Matthew McAlvanah, a spokesman for the United States Trade Representative, said Friday his government "played a leadership role in the TPP, working diligently with the other parties to develop strong rules of origin."