U.S. commanders in Afghanistan are drawing up another plan to deploy about 2,500 additional troops and trainers to the country's north, defense officials said on Friday.

The reinforcements, part of the 30,000-troop increase ordered by President Barack Obama in December, could take part in military operations with German forces already in the area with the aim of protecting vital supply lines.

A large portion of the 2,500 additional troops is expected to be "trainers" to bolster the Afghan national army.

A senior U.S. military official acknowledged that any diversion of forces to the north could dilute the high-priority campaign in the south because of the limited number of forces available.

Reuters