He made the comments at a court appearance in the capital, Addis Ababa, following his arrest in July in a security force crackdown to curb the violence that hit Ethiopia after the killing of popular singer Hachalu Hundessa by unknown gunmen.
It is the most high-profile political case since Prime Minister Abiy Ahmed took office in 2018, with a promise to end decades of authoritarian rule.
Mr Jawar has been charged with 23 others under anti-terrorism laws, as well as legislation related to telecom fraud and the possession of firearms.
Four of the accused have been charged in absentia.
Having returned from exile in the US after Mr Abiy took office, Mr Jawar initially supported the prime minister after he embarked on a series of reforms that saw the unbanning of opposition groups, the release of thousands of political prisoners, and the dropping of terrorism-related charges against exiles, including Mr Jawar.
But the two later fell out, and Mr Jawar became a fierce critic of the prime minister.
He joined the Oromo Federalist Congress (OFC), and stepped down as the chief executive of an influential television station run by the Oromo Media Network (OMN).
The OMN has also been charged with terrorism.