"The use of military units against a sovereign neighbouring state... Is an absolutely unjustifiable step," Zaoralek told ambassador Sergei Kiselev yesterday.
He also called on Russia to "retain the territorial integrity of Ukraine" and to "withdraw its soldiers from Crimea and refrain from provocation that could... End in bloodshed."
Earlier yesterday, Zaoralek said that "if this is the beginning of an invasion to occupy Crimea, it's something with which we have rich experience and we can't agree with it."
On Saturday, Zaoralek and Czech President Milos Zeman likened Russia's moves in Crimea to the Soviet-led 1968 occupation of former Czechoslovakia which crushed a widespread democratic reform movement in the country, claiming over 100 lives.
Czechoslovakia shed communist rule in 1989, four years before it split peacefully into the Czech Republic and Slovakia.