The former Seoul mayor who swept December elections in South Korea is getting used to his new title: Mr. President. Lee Myung-bak has taken his oath of office in a formal ceremony in the South Korean capital.

Performers brought the sights and sounds of South Korea's rich cultural past and present to life Monday, as they heralded the arrival of Lee Myung-bak to the grounds of the country's parliament for his inauguration ceremony.

Incumbent President Roh Moo-hyun, numerous international dignitaries, and some 60,000 spectators looked on as Mr. Lee raised his right hand and formally assumed his title.

Mr. Lee swears to uphold the law and defend his country, formally known as the Republic of Korea. He is now the 17th president in South Korea's history. In his inaugural address, President Lee called economic revival South Korea's "most urgent task."

During his campaign, Mr. Lee promised a more business-friendly environment with fewer regulations and better incentives for innovation. He also promised ties with the United States would receive attention.

Mr. Lee says he will turn the close South Korea-U.S. bond into a future-oriented relationship. He promises to fortify the U.S. alliance under the solid historical trust built between the two nations.

The United States and South Korea have been close allies since Japanese occupation forces on the Korean peninsula were defeated at the end of World War II. About 28,000 U.S. forces are stationed here, to deter a repeat of communist North Korea's 1950 invasion. However, the alliance was widely perceived to have suffered during the Roh administration, primarily over different perceptions of the North.

Mr. Lee has promised to revise what most conservatives here view as an overly generous and uncritical policy of aid and cooperation with Pyongyang. Some experts say South Korean cash and assistance made it easier for Pyongyang to test its first nuclear weapon in October 2006.

Mr. Lee says he is ready to cooperate with North Korea, if it is ready to give up nuclear weapons. He repeats his campaign pledge that if the North gives up nuclear ambitions and opens up the country, the two sides can pave a new cooperative path. That includes working with international investors to raise North Koreans' per capita income to $3,000 a year.

After a symphony performance wrapped up the event, Mr. Lee greeted supporters from his motorcade in a ride around Seoul. His diplomaticschedule was set to start right away, including Monday afternoon meetings with U.S. Secretary of State Condoleezza Rice, and Japanese Prime Minister Yasuo Fukuda.