Four Americans entered Laos Friday and began floating dollar bills down the Mekong River to advertise a $2.4 million reward for missing U.S. servicemen, but the Thai navy scooped up most of the money.

The Americans dumped the money, stamped with the reward offer and sealed in plastic envelopes, into the river after their two boats moved about 220 yards into Laotian waters.They stuffed other bills into a toy boat guided by remote control towards the Laotian shore.

However, a Thai naval patrol boat waved the Americans back to the Thai side of the river and retrieved 62 of about 100 packets tossed into the river, then returned the money.

"It won't work. It's incredibly stupid," said one Thai navy officer.

Two members of the American team were arrested earlier this week after entering Laos. They are believed still held by in Laos.

The Americans are offering $2.4 million to any Laotian, Cambodian or Vietnamese who brings an American out of these nations.

The Americans say the reward money has been pledged by 21 U.S. congressmen and others.