Several thousand US citizens are still unaccounted for in Thailand and Sri Lanka after the tsunami which killed more than 120,000 people.
US officials in the region are looking for thousands of missing people
At least 14 US citizens have been confirmed as dead, state department spokesman Richard Boucher said.
He added that 600 people initially listed as missing were later found but others had been reported as missing.
Canada said four of its nationals were confirmed dead while nearly 90 were missing and unaccounted for.
However, there is confusion over the figures as the Thai government has listed 20 Americans and 13 Canadians among more than 400 dead foreigners.
The Thai list includes 84 bodies identified as foreigners of unknown nationalities.
Mr Boucher said the US dead - seven in Thailand and seven in Sri Lanka - were a mixture of residents and tourists but he gave no further information.
US consular officials have flown to Phuket and Bangkok and teams have gone to Sri Lanka and Indonesia.
"They are trying to go to hospitals, go to hotels, go to morgues, go to any places of congregation, identify Americans and identify the Americans who might not have been heard from," Mr Boucher said.
He said American citizens had been arriving at consular offices in Sri Lanka with only their bathing suits, having lost all their belongings.
Three of the Canadian deaths were in Thailand, and one was in Sri Lanka.
Only two have been identified: Mathieu Lafond, 28, of Repentigny, Quebec, and Gilles Bouchard, a teacher from Gatineau, Quebec.
Dr James Young, who is heading to Thailand on behalf of the Canadian government, told reporters: "It's very difficult, in fact, to establish in the middle of a chaotic situation exactly who is where, and who's been saved and who might be in hospital and who isn't."
He said relatives should gather dental records and DNA samples, such as hair.