A senior administration official has told The Associated Press that President Barack Obama is sending 30,000 more U.S. troops to Afghanistan to be deployed over six months.

In his speech on Tuesday night, Mr. Obama also will lay out a rough timeframe, including some dates, for when the main U.S. military mission will end. The official spoke on condition of anonymity because the details had not yet been announced.

The 30,000 new troops will bring the total in Afghanistan to more than 100,000 U.S. forces. The main mission of the new troops will be to reverse Taliban gains and secure population centres in the volatile south and east parts of the country.