  Anisotropic flow of K's, anti-K's, and lambdas is studied in heavy ion
collisions at SPS and RHIC energies within the microscopic quark-gluon string
model. At SPS energy the directed flow of kaons differs considerably at
midrapidity from that of antikaons, while at RHIC energy kaon and antikaon
flows coincide. The change is attributed to formation of dense meson-dominated
matter at RHIC, where the differences in interaction cross-sections of hadrons
become unimportant. The directed flows of strange particles, $v_1^{K,\bar{K},
\Lambda}(y)$, have universal negative slope at $|y| \leq 2$ at RHIC. The
elliptic flow of strange hadrons is developed at midrapidity at times 3<t<10
fm/c. It increases almost linearly with rising p_t and stops to rise at p_t <
1.5 GeV/c reaching the same saturation value $v_2 ^{K,\Lambda}(p_t) \approx
10%$ in accord with experimental results.
