WITH the eyes of the world upon him, Barack Obama became the first black president of the United States yesterday and promptly vowed to address the challenges facing a country in "crisis".

In an inaugural speech that refused to shy away from the problems ahead, Mr Obama said America needed to confront a "badly weakened" economy and a war against "a far-reaching network of violence and hatred".

But invoking the spirit of the country’s founding fathers, the newly sworn-in president said these challenges would be met.

Throughout the day, people gathered in Washington to witness the truly historic event - the inauguration of a black president.

For the first time, the National Mall leading to the Lincoln Memorial - where in 1963 Martin Luther King delivered his "I have a dream" speech - was opened to accommodate the crowds.

The total size of the audience is expected to have been larger than the record 1.2 million who turned up to see Lyndon B Johnson inaugurated in 1965.

Among those looking on as Mr Obama was sworn in were Muhammad Ali and Dr King’s son Martin Luther King III.

They all had to wait, as the ceremony started later than expected.

Shortly after midday local time, the 47-year-old former senator held Lincoln’s inaugural bible and pledged the oath of office.

But even that did not run entirely smoothly, with chief justice John Roberts stumbling over his words as he conducted the ceremony.

Following the oath, Mr Obama made his first speech as president.