Shares of energy companies gave back some recent gains as oil futures tumbled.

West Texas Intermediate oil futures for November delivery slid by 4.5% in New York after reports from the U.S. military of increased shipping activity in the Strait of Hormuz.

President Donald Trump also signaled an openness to diplomacy between the U.S. and Iran at the United Nations General Assembly meeting later this week.

Oil has now slipped almost 10% in four sessions, the biggest four-day retreat in a month.

The Trump administration has proposed investing $5 billion in a new fund that would help Middle East countries rebuild energy infrastructure battered in the Iran war and reduce their reliance on the Strait of Hormuz to transport oil and gas, according to U.S. and Middle Eastern officials and documents seen by The Wall Street Journal.

Qatar could restore normal operations at parts of its liquefied natural gas facilities within weeks of the reopening of the Strait of Hormuz, the Minister of State for Energy Affairs Saad Sherida Al-Kaabi said, even as extensive damage from Iranian attacks is expected to constrain production for years.