Images show border patrol agents attempting to push back migrants.

The U.S. Department of Homeland Security has called new footage of border patrol agents on horseback attempting to push back migrants as they cross the Rio Grande "extremely troubling."

Watch video on channel "ABC News"
Tens of millions on alert as massive weather systems take aim.

Tens of millions on alert as massive weather systems take aim.

Part of the West Coast is in the path of an atmospheric river storm, which is triggering heavy rain and could lead to flooding.

Gun violence takes toll on Philadelphia’s youth

Gun violence takes toll on Philadelphia’s youth

One student said his commute to school is like passing through a "war zone."

US postmaster general tries to reassure Americans ahead of holidays.

US postmaster general tries to reassure Americans ahead of holidays.

Louis Dejoy said the postal service is adding capacity and will be ready for the holiday season.

Trump is ‘calling the shots’ for Republicans: Donna Brazile.

Trump is ‘calling the shots’ for Republicans: Donna Brazile.

The Powerhouse Roundtable breaks down the latest news on “This Week.”

Vaccines are ‘likely’ to be available to children 5-11 early Nov.

Vaccines are ‘likely’ to be available to children 5-11 early Nov.

George Stephanopoulos interviews Dr. Anthony Fauci on “This Week.”