TOKYO (Reuters) - U.S. Commerce Secretary Wilbur Ross is expected to join Vice President Mike Pence for a bilateral economic dialogue in Tokyo next month, a Japanese government official with direct knowledge of preparations said on Thursday, dashing Tokyo’s hope of leaving thorny issues on trade off the negotiating table. Participants of the dialogue, led by Pence and Japanese Deputy Prime Minister Taro Aso, will hold their first round of talks in Tokyo on April 18 to discuss issues ranging from macroeconomic policy, infrastructure investment and trade. The dialogue will be a major test of U.S. President Donald Trump’s confrontational approach to trade. Senior administration officials, including Ross, have signaled they would press Japan to remove non-tarrif trade barriers and buy more U.S. products. Japan, which proposed the dialogue, had hoped to keep contentious issues like auto and agriculture trade out of the talks by proposing an agenda focused on infrastructure investment and energy. One of Tokyo’s strategy was to keep the bilateral dialogue as informal as possible so Aso can deal directly with Pence, who is regarded as having a less confrontational view on trade compared with others in the Trump administration, Japanese government officials said. “The agenda is vague now, but if friction comes up in the future, our plan is to say let’s discuss that in the Aso-Pence dialogue and then use the dialogue to diffuse any problems,” one of the officials said on condition of anonymity as he was not authorized to speak publicly. The participation of Ross heightens the chance the dialogue would serve as a venue to discuss a bilateral trade deal, which could put Japan under U.S. pressure to open up heavily-protected areas like agriculture and pharmaceuticals, the officials said. Hiroshige Seko, Japan’s ministry of economy, trade and industry, and Foreign Minister Fumiko Kishida will also join the dialogue, the government officials said. Ross has been known to have close ties with Japan, having led a firm investing in the country since 1997 and serving as chairman of the Japan Society - a non-profit organization promoting bilateral relations, since 2010. 