An oil tanker was hit by a projectile on Wednesday in waters near Qatar, according to a report from the United Kingdom Maritime Trade Operations (UKMTO), marking a rare attack in the heart of the Persian Gulf.

UKMTO said the vessel was struck in waters north of Madinat ash Shamal, the northernmost city in Qatar. Casualties have been reported, and authorities have launched an investigation, but they did not disclose the identity of the vessel involved or assign responsibility for the attack.

This is the first time in roughly a month that an oil tanker has come under attack in the heart of the Persian Gulf. On September 9, UKMTO said a vessel was hit by an unidentified projectile approximately 28 nautical miles southeast of Al-Faw, Iraq. Since then, most attacks have been concentrated in and around the Strait of Hormuz.

The attack comes at a time of renewed escalation in tensions between Washington and Tehran. According to two U.S. government officials, the White House has asked the Pentagon to draw up strike options against Iran so they could be carried out before the U.S. midterm elections. Reports say the scale and targets of potential strikes, as well as whether the administration will ultimately move forward with the plans, remain under discussion.