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We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources, namely, 3C 111, 3C 120, and 3C 390.3. The lines are detected with high significance according to both the F-test and extensive Monte Carlo simulations. Their likely interpretation as blueshifted Fe xxv and Fe xxvi K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range v≃ 0.04–0.15c. A fit with specific photoionization models gives ionization parameters in the range log ξ≃ 4–5.6 erg s− 1 cm and column densities of N H≃ 10 22–10 23 cm− 2. These characteristics are very similar to those of the ultra-fast outflows …