Spanish security forces found a third explosive device hidden in a mailed parcel to air force base in Torrejon de Ardoz outside Madrid, newspaper El Mundo reported Thursday morning.
After scanning the envelope by X-ray, Air Force security officers determined it contained "a mechanism", the ministry statement said. On Thursday morning, police were still analysing the parcel, which was addressed to the base's satellite centre.
Two letter bombs were found on Wednesday addressed to the Ukrainian embassy in Madrid and to a weapon manufacturer in Zaragoza, in northern Spain, police said.
The first one exploded causing minor injuries to a Ukrainian official.
