TOKYO, May 9 (Xinhua) -- The Japanese government on Wednesday said it was concerned about the potential ramifications following the United States' decision to withdraw from the international deal on Iran's nuclear program.

"It would be regrettable if the U.S. pullout has a major impact to the extent of making it difficult to maintain the Iran nuclear agreement," Foreign Minister Taro Kono was quoted as saying in a statement on the matter.

"We hope that the countries involved will continue to deal with the issue in a constructive manner," Kono said.

U.S. President Donald Trump said on Tuesday that his country would exit from the deal struck with Iran and said the highest level of sanctions would be imposed against Iran.

The unilateral move by the U.S. runs contrary to a deal struck by Trump's predecessor Barack Obama.

The deal, struck between Iran, Britain, China, France, Germany, Russia and the United States in 2015, saw heavy economic sanctions slapped on Tehran lifted in exchange for it curbing its nuclear activities.

Kono said that Japan will work closely to try and keep the deal in place, while looking into the possible affects of the U.S. withdrawal from the deal and developments henceforth.

For Japan's part, as well as further unsettling delicate geopolitical situations in the Middle East, resource-poor Japan is reliant on Iran for around 7 percent of its crude oil imports.

In theory, if sanctions are slapped on Iran, then Japan would be forced to cut its crude oil imports from Iran, which is Japan's fifth largest provider, with Saudi Arabia and the United Arab Emirates being its top two.

When sanctions were lifted against Tehran in 2016, exports from Japan to Iran of industrial machinery and steel products increased by three times compared to when the sanctions were applied.

Japan has around 30 companies spanning electronic makers and trading houses with branches in Iran, with the number of Japanese workers there steadily increasing over the past two years.

As economists here have pointed out, the U.S. departure from the deal and new unilateral sanctions applied to Tehran could severely hurt Japanese trade ties with Iran.