The waters off Oman are emerging as a hot spot for ship-to-ship transfers of Russian oil heading to India, as the US steps up scrutiny of the flows.

New Discovery is the latest tanker to transfer its load of Russian crude to another vessel near the Omani port of Sohar this week. The ship had been signaling Sikka in western India as its destination from early March, before idling off the country’s west coast for more than a week and then traveling back to Oman to make the transfer, according to Bloomberg ship-tracking.

The Caroline Bezengi, which received about 1 million barrels of Urals crude from the New Discovery, isn’t currently signaling a destination, Kpler data show.

Transferring oil from one vessel to another is often done to mask the origin of the cargoes, and sometimes to split up the shipment to meet draft restrictions at certain ports. Oman and Fujairah in the United Arab Emirates are common locations for transfers in the Middle East, while in Asia they’re often done in the waters off Malaysia.

Oman now seems to be gaining in popularity as a location for the reloading of Russian barrels. Prior to the New Discovery, three other tankers have passed their cargoes of Urals crude to other vessels in the country’s waters since early February. The ships that received the oil then discharged their cargoes at Indian ports.

Read More: More Oil Tankers Behave Oddly Delivering Russian Crude to India

India has been a major buyer of discounted Russian oil since the invasion of Ukraine, but tighter enforcement of US sanctions is now disrupting the trade. All of the country’s refiners are refusing to take oil carried on PJSC Sovcomflot tankers.

Sohar is “arguably one of the biggest STS places in all of the Middle East and Asia” and there’s no crude imported there, said Viktor Katona, lead crude analyst at data intelligence firm Kpler. “I wouldn’t be surprised if India’s solution is to have the Russians deliver the barrels to Sohar or the UAE territorial waters and then trans-ship it onto tankers that are already OK for them compliance-wise.”