MIAMI (AP) — Hurricane Sandy has gained strength as it swirls toward the East Coast.

The National Hurricane Center says the hurricane's wind speed increase early Monday to 85 mph with additional strengthening possible.

Sandy has forced the shutdown of mass transit, schools and financial markets, sent coastal residents fleeing for higher ground, and threatens to bring a dangerous mix of high winds, soaking rain and a surging wall of water.

Sandy has stayed on a predicted path that could take it over Washington, Baltimore, Philadelphia and New York on its way to a collision course with two other weather systems, creating a superstorm with the potential for havoc over 800 miles from the East Coast to the Great Lakes.