Two pilots, flying over the Pacific Ocean, surpassed the world distance record for human flight in a gas-filled balloon on Thursday. The pilots, an American named Troy Bradley and Russian national Leonid Tiukhtyaev, collectively known as the “Two Eagles,” have so far covered a distance of over 5,500 miles since they took off from Japan on Sunday, according to a flight tracker on their website.

However, because the rules of international aviation require the current record of 5,209 miles -- set in 1981 -- to be exceeded by at least 1 percent to establish a new record, the pilots' claim would have to be ratified by the U.S. National Aeronautic Association and the Switzerland-based Federation Aeronautique Internationale, a process that might take several weeks.

“While the pilots and team are excited about these accomplishments, they remain focused on the most important objective of all -- a safe landing after a successful crossing of the Pacific Ocean,” the Two Eagles team said, in a statement released Thursday. “The balloon continues to move south along the California Coast, with a landing anticipated in Baja California sometime on Saturday.”

Currently, the balloon is at a height of nearly 20,000 feet and is about 225 miles off the U.S. West Coast.

“The next milestone will be the gas balloon world record for time aloft,” the team said, in a statement published on their website. The existing duration record was set in 1978 when a team of pilots made the first trans-Atlantic balloon flight, spending 137 hours, 5 minutes and 50 seconds in a gas balloon. As of now, the Two Eagles team has stayed aloft for nearly 132 hours.

The Two Eagles gas balloon, unlike purely hot-air or composite “Roziere Balloons,” is a helium-filled balloon. The capsule in which the pilots have spent the last six days is about 7 feet long, 5 feet high, and 5 feet wide, and is equipped with cold weather gear, including sleeping bags and heaters, as well as a simple toilet.