  We have demonstrated the effect of pressure on the steplike metamagnetic
transition and its associated magnetostriction in
(Eu$_{1-x}$Gd$_{x}$)$_{0.6}$Sr$_{0.4}$MnO$_{3}$ ($x=0$ and 0.1). The critical
field initiating the field induced ferromagnetic transition in both samples is
lowered by the applied pressure. The further application of external pressure
up to 1.2 GPa on the $x=0$ parent sample causes a spontaneous ferromagnetic
transition with a second-oder like character, leading to collapses of the
steplike transition and its concomitant lattice striction. These findings
indicate a crucial role of the low-temperature phase separated state
characterized by a suppressed magnetization upon decreasing temperature.
