The 5,600 recently departed soldiers due to be called back to active duty starting next week include 115 in northern New England, the Army said Friday.

The first callup letters are expected to arrive in mailboxes Tuesday.

Most of those affected have specialties that are in short supply: truck drivers, mechanics, supply clerks, administrative clerks and combat engineers.

Julia Collins of the Army’s Human Resources Command in St. Louis said the numbers – still tentative – are 58 from Maine, 40 from New Hampshire and 17 from Vermont. There are no names yet.

Those called up could be sent to Iraq or Afghanistan as early as fall. They will be kept on active duty for 18 months to two years.

The call-up will be done in three increments from July to December.

It is the first large-scale call-up from what is called the Individual Ready Reserve since 1991.