  The spatial string tension across a crossover from the low temperature phase
to the high temperature phase is computed in QCD with two flavors of
non-perturbatively improved Wilson fermions at small lattice spacing a \sim
0.12fm. We find that in the low temperature phase spatial string tension agrees
well with zero temperature string tension. Furthermore, it does not show
increasing for temperatures up to T = 1.36 T_{pc}, the highest temperature
considered. Our results agree with some theoretical predictions.
