  Recent BeppoSAX observations of Arp 299, a powerful far-IR merging starburst
system composed of IC 694 and NGC 3690, clearly unveiled for the first time in
this system the presence of a strongly absorbed active galactic nucleus (AGN).
However the system was not spatially resolved by BeppoSAX. Here we present the
analysis of archival Chandra and (for the first time) XMM-Newton observations,
which allow us to disentangle the X-ray emission of the two galaxies. The
detection of a strong 6.4 keV line in NGC 3690 clearly demonstrates the
existence of an AGN in this galaxy, while the presence of a strong 6.7 keV
Fe-Kalpha line in the spectrum of IC 694 suggests that also this nucleus might
harbor an AGN. This would be the second discovery of two AGNs in a merging
system after NGC 6240.
