Firebrand Russian nationalist politician Vladimir Zhirinovsky, a key figure in the country's post-Soviet history, has died at the age of 75, the head of the lower house of parliament said Wednesday, AFP reported. State Duma chairman Vyacheslav Volodin said Zhirinovsky -- who was reported to have been in grave condition after being hospitalised in early February with Covid -- had died after a "serious and prolonged illness".