One of the largest earthquakes in the region, with a magnitude of 7.0, has hit Haiti Tuesday, killing possibly thousands, leveling buildings and destroying infrastructure. Reports say thousands of people are living out on the streets in the dust-covered capital.

The quake has been declared "catastrophic" by U.S. Secretary of State Hillary Rodham Clinton.

Thousands remain missing, including personnel at the United Nations headquarters.

Relief agencies from numerous countries have begun deploying aid, but the full scale of the disaster is still unknown.