Ukraine's parliament Thursday fired the powerful head of the SBU state security service after he fell foul of President Petro Poroshenko and became embroiled in a conflict with the nation's chief prosecutor.

"The Verkhovna Rada (parliament) supported my proposal to dimiss Valentyn Nalyvaychenko from his post as head of the SBU," Poroshenko tweeted after 248 lawmakers in the 450-seat chamber supported the president's formal request.