WASHINGTON — US President Barack Obama will announce his new Afghan strategy in an address to the nation Tuesday evening from the prestigious West Point military academy, the White House said.

Obama is widely expected to send tens of thousands more troops to battle an increasingly fierce Taliban insurgency in one of the defining moments of his young presidency.

"The president will address the nation on Tuesday at 8:00 pm (0100 GMT Wednesday) from the military academy at West Point on Afghanistan," White House spokesman Robert Gibbs told journalists.