Prime Minister Shinzo Abe has dropped his plan to visit Iran this summer, government sources said Tuesday, as U.S. President Donald Trump has taken an increasingly tough line against Tehran.

The government was making arrangements for Abe to visit the Iranian capital in mid-July and hold talks with President Hassan Rouhani. The trip would have made Abe the first Japanese leader to visit the country since Takeo Fukuda in 1978.

But the sources said the government told the Iranian side by late June that Abe would not be able to make the trip.

The decision was made in light of Trump’s push to isolate Iran and choke off its oil exports after he pulled the United States out of the 2015 Iran nuclear agreement in May.

The United States has urged Japan and its other allies to stop buying Iranian crude oil entirely by Nov. 4.

But Japan, which has traditionally maintained stable relations with Iran, has told the Trump administration it cannot further reduce or halt Iranian crude imports, citing a possible negative impact on the economy, according to the sources.

Tokyo had for decades relied on Iran as one of its key sources of oil. But crude oil from Iran now only accounts for about 5 percent of the country’s total oil imports, according to the Ministry of Economy, Trade and Industry.

However, it is highly likely that Washington’s request to increase pressure on Tehran will be brought up by U.S. Secretary of State Mike Pompeo when he makes a two-day visit to Tokyo this weekend.

The government will continue to explore the possibility of Abe visiting Iran by looking at how relations between Washington and Tehran develop in the months ahead, the sources said.

After abandoning the plan, Abe is now scheduled to stop in Saudi Arabia and Egypt in the Middle East following visits to Brussels and Paris during his eight-day tour beginning July 11.