Change was stamped on the White House yesterday as Barack Obama shattered racial barriers to become the first African American president of the United States.

Minutes after being sworn in as the 44th president of the US, he promised to free the country from the grip of profound economic troubles and steer¹ away from wars in two distant lands.

"Today I say to you that the challenges we face are real," Obama said after taking the oath of office on the same copy of the Bible that Abraham Lincoln used at his inauguration² in 1861. "They (the challenges) are serious and they are many," he said. "They will not be met easily or in a short span of time. But know this, America - they will be met."

The crowd that gathered on National Mall from the Capitol to beyond the Washington monument for the presidential inauguration had swelled³ to a record 2 million by noon, just before he was sworn in. The multitude was filled with people from all backgrounds, race and color, with Obama's triumph being a special and emotional moment for black Americans.

With his wife, Michelle, holding the Bible, Obama, the 47-year-old son of a white mother from Kansas and a black father from Kenya, promised to take "bold and swift" action to restore the economy by creating jobs through public works projects, improving education, promoting alternative energy and relying on new technology.

"Starting today, we must pick ourselves up, dust ourselves off, and begin again the work of remaking America," Obama said. He assumes power over a country longing⁴ for change after former president George W. Bush's eight divisive years in the White House, an era that witnessed the September 11, 2001, terror attacks, the beginning of wars in Afghanistan and Iraq and an economic collapse⁵ not seen since the 1930s Great Depression.

The new president used strong language in pledging to confront terrorism, nuclear proliferation and other threats from abroad, warning the US' enemies: "You cannot outlast⁶ us, and we will defeat you."

But he also signaled a clean break from some of the Bush administration's policies on national security. "As for our common defense⁷, we reject as false the choice between our safety and our ideals." The US is "ready to lead once more," he said.

He said he knows that some people are skeptical⁸ of his ability to fulfill⁹ the hope that he has raised to lead the US in a new direction. "What the cynics fail to understand is that the ground has shifted beneath them - that the stale political arguments that have consumed us for so long no longer apply," Obama said.

"Let it be said by our children's children that when we were tested we refused to let this journey end, that we did not turn back nor did we falter¹⁰; and with eyes fixed¹¹ on the horizon and God's grace upon us, we carried forth¹² that great gift of freedom and delivered it safely to future generations."

Obama promised the world a new America that listens to all voices. But he vowed¹³ to spare nothing to keep the US safe, addressing the Islamic world directly.

"To the Muslim world, we seek a new way forward, based on mutual¹⁴ interest and mutual respect," Obama said. "To those leaders around the globe who seek to sow conflict, or blame their society's ills on the West - know that your people will judge you on what you can build, not what you destroy.

"To those who cling to power through corruption¹⁵ and deceit and the silencing of dissent¹⁶, know that you are on the wrong side of history; but that we will extend a hand if you are willing to unclench your fist."