  We report on gamma-ray analysis of the region containing the bright TeV
source HESS J1640-465 and the close-by TeV source HESS J1641-463 using 64
months of observations with the Fermi Large Area Telescope (LAT). Previously
only one GeV source was reported in this region and was associated with HESS
J1640-465. With an increased dataset and the improved sensitivity afforded by
the reprocessed data (P7REP) of the LAT, we now report the detection,
morphological study and spectral analysis of two distinct sources above 100
MeV. The softest emission in this region comes from the TeV source HESS
J1641-463 which is well fitted with a power law of index Gamma = 2.47 +/- 0.05
+/- 0.06 and presents no significant gamma-ray signal above 10 GeV, which
contrasts with its hard spectrum at TeV energies. The Fermi-LAT spectrum of the
second TeV source, HESS J1640-465 is well described by a power-law shape of
index Gamma = 1.99 +/- 0.04 +/- 0.07 that links up naturally with the spectral
data points obtained by the High Energy Stereoscopic System (H.E.S.S.). These
new results provide new constraints concerning the identification of these two
puzzling gamma-ray sources.
