Lt. Gen. Udomdej Sitabutr, Army Region 1 commander, said all nine people aboard the Black Hawk died, including Maj. Gen. Thawan Ruangsri, commander of the Surasee 9th Infantry Division, the Thai News Agency reported.
Udomdej said the crash scattered the helicopter's fragments in the mountainous Kaeng Krajan National Park, but there was no explosion. Wind shear was the likely cause.
He said Myanmar soldiers helped in the search.
The Black Hawk crew had set out Tuesday to recover the bodies of five soldiers who died in a helicopter crash in the remote area Saturday.