The Arakan Army, for its part, said that it had released old people, women and children from the ferry before taking the hostages away, and that it only took armed soldiers and police officers hostage because they had “pretended to be civilians.”

Khaing Thu Kha, a spokesman for the Arakan Army, said his colleagues had been unable to protect all of the hostages from the Tatmadaw attack along the May Yu River, and that the government’s helicopters had fired “indiscriminately” on the three escape boats, sinking two of them.

U Than Naing, a trader who lives in Rakhine State , said he is the uncle of a young man whom he feared may have died in the helicopter attack.

“The military said 14 have been rescued,” Mr. Than Naing said on Monday. “But they don’t say who they are and I fear that no one survived.”

The kidnapping took place on a ferry carrying passengers upriver from Sittwe. The Tatmadaw did not release the names of the rescued personnel, and it vowed to continue “a combined air and land” operation to rescue the remaining hostages. It said the kidnapped group included a mix of soldiers, police officers and government workers.

The Arakan Army has been fighting to create an independent state along the lines of the ancient Arakan kingdom that once ruled the area — and which fell to an invading Burmese army more than two centuries ago.

The insurgent group announced the ferry abduction on Sunday, two weeks after the Myanmar authorities said that 31 people, mostly firefighters, had been kidnapped from an express bus in Rakhine State. The armed men who conducted that operation wore soccer uniforms and were later identified by the Tatmadaw as members of the Arakan Army.