Record-breaking heat will continue to blanket most of the central and eastern United States over the coming days, with peak heat indices potentially reaching 115 degrees Fahrenheit (about 46 degrees Celsius), the National Weather Service posted on its website on Thursday.

According to US media outlets, an estimated 163 million people in the country are currently affected by the extreme heat.

Also on Thursday, major cities including Boston, New York, Washington, Pittsburgh and Atlanta were placed under the highest level of heat risk. Authorities predict that the high temperatures in most regions will persist through July 4, and the celebrations for the 250th anniversary of the founding of the United States are expected to be impacted by the hot weather.