ARLINGTON, Va. (AP) — Arlington National Cemetery has opened a new section of gravesites with the burial of two Civil War soldiers recently discovered at a northern Virginia battlefield.

The cemetery dedicated its 27-acre (11-hectare) Millennium site Thursday afternoon. The expansion adds 27,000 spaces, including more than 16,000 reserved for cremated remains in a new columbarium.

The first ground burials in the new location were two unidentified sets of remains found among severed limbs in a surgeon's pit at Manassas National Battlefield Park. Experts believe the two were Union soldiers who died during the Second Battle of Bull Run in 1862.

More than 400,000 veterans are interred at Arlington, which is running out of room. The military is considering tighter eligibility requirements to preserve the cemetery's ability to accept more burials.