The IBIS imager on board INTEGRAL has localized so far 723 hard X-ray sources in the 17-100 keV energy band with a point source location accuracy of a few arcminutes. The cross-correlation between the IBIS sources and the Chandra/ACIS data archive resulted in a sample of 4 not yet identified objects with a possible counterpart. We present here the results of Chandra X-ray Observatory observations of these hard X-ray sources discovered by the INTEGRAL satellite, providing the sub-arcsecond

more »

... zations necessary to pinpoint the optical and/or infrared counterpart and measuring their soft X-ray energy spectrum. All these informations are mandatory to disentangle the nature of these high energy emitters.