U.S. President Donald Trump speaks with Shinzo Abe, Japan's prime minister, during a dinner on May 26, 2019 in Tokyo, Japan.

U.S. President Donald Trump concluded his four-day visit to Japan on Tuesday amid uncertainty about whether a trade deal between the two countries could come within months.

Trump had indicated during the trip that there will be trade announcements between the two sides "probably in August," and that the trade gap between the two countries could be "straightened out rapidly."

But Japan's economy minister sought to play down expectations for a fast deal, saying Tuesday that the U.S. leader's comments reflected Trump's hopes for quick progress in negotiations.

"When you look at the exact wording of his comments, you can see that the president was voicing his hopes of swift progress in talks toward something that is mutually beneficial," Toshimitsu Motegi told reporters at a regular cabinet meeting, according to Reuters.

The U.S. had a "large trade deficit" of $67.6 billion in goods with Japan in 2018, according to the office of the U.S. Trade Representative, and Trump has indicated he wants a a substantial reduction in the trade imbalance between the countries.

Washington and Tokyo, led by Prime Minister Shinzo Abe, have been wrangling over tariffs on automobiles and agricultural products for months.

"Optically, I think the trip went off as well as either side could have expected," Matthew Goodman, senior advisor for Asian economics at the Center for Strategic and International Studies, told CNBC's Chery Kang on Tuesday.

Addressing Trump's comment that some sort of an agreement could come by August, Goodman expressed some doubts: "It's going to take longer than that."

"I think (Trump) was trying to indicate that he wouldn't put pressure on Prime Minister Abe ahead of the upper house elections in Japan in July, and so it was going to take until August to get this done," he said.

However, with disagreements over agriculture and automobiles, the issues will likely take longer than a few months to be resolved, particularly given the complicated legislative process in both countries, Goodman added.

Last week, Motegi, who is in charge of trade talks, said after a meeting with U.S. Trade Representative Robert Lighthizer that there were still differences between the two sides that need to be ironed out.

"We've agreed that we'll strive to narrow the gap, including through possibly holding working-level talks," Motegi said at the time, adding that no schedule had yet been set for future talks.

— Reuters contributed to this report.