Japanese and U.S. authorities launched a search Friday after radio contact was lost early in the morning with a hot-air balloonist attempting to cross the Pacific Ocean from Tochigi Prefecture to North America, one of his supporters said.

"We could not contact him since his last call made at 3 a.m. today (Friday)," Toshitsugu Ichihara told The Japan Times over the phone, adding that the support group for balloonist Michio Kanda, 58, asked the authorities to begin the search.

Kanda, from Saitama Prefecture, lifted off at 5 a.m. Thursday in his hot-air balloon Starlight on a solo flight across the Pacific. He planned to make the crossing in about 60 hours, and would be the first Japanese to achieve the trans-Pacific feat, which he had previously attempted in vain.

After taking off, Kanda maintained regular contact with his supporters every two hours.

When he radioed for the last time at 3 a.m. Friday, he told them the balloon was flying without any trouble at an altitude of 4,800 meters, located at 44 degrees and 30 minutes north latitude and 177 degrees and 5 minutes west longitude, in the middle of the North Pacific, according to Ichihara.

The supporters contacted the authorities at around 9 a.m., Ichihara said. Kanda's balloon was equipped with an emergency position-indicating radio beacon that can be activated manually.