Obama thanks Portugal for Bo, the dog

US President Barack Obama won a rare laugh at the NATO summit by hailing hosts Portugal as the homeland of the US first family's newest member, his daughters' dog.

Obama was speaking after very serious talks with Portugal's Prime Minister Jose Socrates on the financial crisis, European missile defence and the future course of the NATO's brutal war in Afghanistan.

He thanked Portugal for its support, and added: "And I understand that there's been a fair amount of interest here about how my family has been enriched by Portugal as well, specifically Bo, our dog.

"He is the most popular member of the White House," he said to laughter.