Armenian investigators on Thursday charged former President Robert Kocharyan with usurping power and filed a court motion to arrest him, the special investigation service said.
The move comes three months after a power change in the ex-Soviet country following weeks of mass protests against corruption and cronyism.
Kocharyan served as Armenia's second president from 1998 to 2008 and investigators have charged him with an attempt to overthrow the constitutional order during post-election events in March 2008, when his ally Serzh Sarksyan was elected the next president.
In February-March 2008 the opposition held protest rallies, contesting the results of the election and claiming that their candidate, Levon Ter-Petrosyan, had won the vote.
The protests were dispersed and 10 people were killed in clashes with police. The Constitutional Court upheld the election results.
Nikol Pashinyan, an opposition activist at the time who was imprisoned in June 2009 on charges of fomenting unrest during post-election protests, was elected prime minister by parliament on May 8 this year.
Kocharyan said the latest charges were politically motivated, but added he was ready to spend time in prison.
"These charges are fiction, fabricated, unjustified and have a political implication," he told an independent Armenian Yerkir Media TV.
Kocharyan also said the most likely development was his arrest, but he did not intend to run away.
"I'm going to go sit in prison and fight to the end."