New York  - UN Secretary General Ban Ki-moon on Wednesday sent his "warmest congratulations" to president-elect Barack Obama, vowing to work closely with him to resolve global issues.

"These are profound challenges that require collaboration and cooperation," Ban said in the first message to Obama's historic election victory to become the 44th US president.

"Today, Senator Barack Obama is America's choice, I look forward to working with the new administration to fulfil our common goals and objectives," Ban said.

Ban said Obama has preferred to resolve global issues through dialogue and he expects the US to take a more active participation in UN activities. (dpa)