  By means of solving the Bethe-Salpeter equation with the minimal perturbative
kernel (ladder approximation) in the arbitrary covariant gauge, there was found
a series of intercepts of meson Regge trajectories associated with colorless
singularities of the four-quark Green function in SU($N_c$) quantum
chromodynamics with massless quarks. The gauge and renorm-invariance of the
result is grounded.
