  We present a non-perturbative computation of the running of the coupling
alpha_s in QCD with two flavours of dynamical fermions in the Schroedinger
functional scheme. We improve our previous results by a reliable continuum
extrapolation. The Lambda-parameter characterizing the high-energy running is
related to the value of the coupling at low energy in the continuum limit. An
estimate of Lambda*r_0 is given using large-volume data with lattice spacings a
from 0.07 fm to 0.1 fm. It translates into Lambda_{MSbar}^{(2)}=245(16)(16) MeV
[assuming r_0=0.5 fm]. The last step still has to be improved to reduce the
uncertainty.
