Obama pays tribute to Martin Luther King

Both Obama and King are African Americans.

In the evening, the president-elect will attend three private dinners to honor former secretary of State Colin Powell, Vice President-elect Joe Biden and Senator John McCain, the 2008 Republican presidential nominee, for their public service.

U.S. President-elect Barack Obama hugs a girl during a visit to Sasha Bruce House, an emergency shelter for teens in Washington, January 19, 2009. (Xinhua/Reuters Photo)

Meanwhile, Washington is braced for unprecedented crowds for Tuesday's inauguration.

More than 2 million people are expected to attend the historic event.

Some snow showers are forecast for Washington DC during Monday and temperatures are set to drop to well below freezing overnight.

The weather for Tuesday is forecast to be colder than average, around zero Celsius degrees.