WASHINGTON, Aug. 4 (Xinhua) -- At least four people were killed as tropical storm Isaias on Tuesday battered the U.S. East Coast with heavy rain and strong wind.

A tornado spawned by the storm killed two people at a mobile home park in Bertie County, North Carolina, Governor Roy Cooper said.

Two others were killed by falling trees toppled by the storm in Maryland and New York City, the authorities said.

More than 2.2 million customers of electricity services were without power along the East Coast, including 1.3 million in New Jersey, according to a Fox News report.

The U.S. National Hurricane Center (NHC) in Miami reported maximum sustained winds of 65 mph as of 3 p.m. ET on Tuesday, 9 mph shy of officially being a hurricane.

"Strong and damaging winds will continue to spread northward across the New York City metropolitan area, including eastern Long Island and southern New England, that could knock down trees and power lines," the NHC said.