Three tankers were reportedly damaged in the Strait of Hormuz on Thursday as Iran continues its campaign to restrict shipping through the waterway.

Iran’s Islamic Revolutionary Guard Corps (IRGC) claimed that two tankers hit mines and a third caught on fire in the Strait. A British maritime security organization has recorded attacks on five vessels in the region since Sunday. 

In October, Iran escalated its attacks on tankers transiting the Strait outside of Tehran’s protocols. “The aim is to frustrate efforts by the United States and its allies to bring ⁠down global oil prices,” an Iranian official told Reuters last month. A second explained, “Just when they think they are getting close to the point where prices will fall, we will push them away from it. This is a game of chess. Such vessels would be safe nowhere, even outside the Strait of Hormuz.”

Iran attacked at least 35 vessels in the region last month, a record high during the nine-month-long war. 

The Strait of Hormuz has become a major issue in the war. Before the war, the Strait operated as an international shipping route. After the US and Israel attacked Iran, Tehran asserted control over shipping through the waterway and imposed new transit protocols. 

Iran has attacked vessels attempting to use the waterway without Tehran’s permission. As a fifth of the global oil supply exits the Persian Gulf through the Strait, the US has escorted tankers through the waterway to keep oil prices from spiking. 

The attacks come amid reports that President Donald Trump is preparing to resume large-scale strikes on Iran following the midterm elections. One source told Reuters that Trump delayed the bombing campaign until after Tuesday’s vote. “He is planning to bomb Iran. Don’t listen to what he’s saying. He held off because of the midterms. We asked him to hold off until the midterms,” they said.