KIEV, Feb. 4 - The Prosecutor General’s Office said Monday it filed a lawsuit seeking to cancel the sale of a majority stake in aluminum smelter ZALK to a Russian group seven years ago, alleging the group has failed to meet investment obligations.

The stake of 68.01% in ZALK was purchased by the Russian consortium AvtoVAZ-Invest in February 2001 for $70 million and is now effectively controlled by Rusal, Russia’s aluminum giant.