The U.S. Embassy in Laos said Wednesday it is trying to determine the fate of two Americans arrested after they tried to advertise a $2.4 million reward for the return of U.S. soldiers in Indochina.

An embassy spokesman, contacted by telephone in Vientiane, said the embassy received no response to a note sent to the Laotian Foreign Ministry asking about the status of the Americans, who were seized by authorities Sunday.Donna Long, 45, and James Copp, 43, had planned to float thousands of dollars down the Mekong River offering the reward to any Laotian, Cambodian or Vietnamese who brought an American prisoner of war to the International Red Cross.

The two had also planned to cross to the Laotian bank of the boundary-marking river and advertise the award to local villagers.