It all started with a box of cookies.

Maersk said this week that it successfully delivered a small box of cookies to one of its tanker ships in a seaport town in Denmark. The shipping giant touted it was the first time a drone was used to deliver goods to a vessel.

Maersk operates a large fleet of tankers that ship flammable materials, such as crude oil and gas, across seas and oceans. Typically, when one of its tankers needs spare parts or mail delivered to workers, the company sends out a flat-bottomed boat called a barge to ship the goods to the tanker.

The company is looking to use drones to cut down on the costs it takes to use barges for deliveries, and it said it could save $3,000 to $9,000 per vessel each year.

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“It’s a totally new step in delivery to vessels,” said Captain Peder Georg Kastrup Christensen, in a statement. “Today it’s cookies. Another time it might be medicine which we need to treat someone on board.”

It took about one-and-a-half minutes for the drone to deliver the cookies across a distance of one kilometer.

Besides experimenting with drone delivery, Maersk revealed it is also experimenting with using the flying robots for installations, inspections of cargo tanks, and monitoring for pirates.

Maersk isn’t the only company exploring the use of drones for delivery.

Amazon amzn , Google goog , and Walmart wmt have all sought approval from the U.S. Federal Aviation Administration to let them test drone deliveries.

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Compared to other countries like France, Denmark, and Canada, the United States is more stringent regarding the commercial use of drones. U.S.-based companies must be certified on a case-by-case basis with the FAA before employing drones. Even when they win approval, they must comply with many rules, including not flying the drones at night and out of site of the operator’s eyes.

That’s partly why Amazon has been testing drones for deliveries outside the U.S. in places like United Kingdom, Canada, and the Netherlands.