The Southeast Asian country has been in chaos since the February coup, with more than 1,400 killed in a subsequent crackdown on dissent, according to a local monitoring group.
Junta opponents - including allies of Suu Kyi’s National League for Democracy - have gone into hiding across the country, and “People’s Defence Forces” have sprung up across the country to take on the military.
Phyo Zeyar Thaw, a member of the NLD arrested in November, was sentenced to death for offences under the anti-terrorism act, the junta statement said.
Prominent democracy activist Kyaw Min Yu - better known as “Jimmy” - received the same sentence from the military tribunal, the statement added, carrying pictures of both men.
Their sentences were also read out on state media’s nightly news.
The junta has sentenced dozens of anti-coup activists to death as part of its crackdown on dissent but Myanmar has not carried out an execution for decades.
Phyo Zeyar Thaw - whose real name is Maung Kyaw - was arrested at an apartment in the commercial hub Rangoon following a “tip-off and cooperation from dutiful citizens,” according to the junta.
The former lawmaker - who also goes by the name Phyo Zeyar Thaw - was in possession of two pistols, ammunition and an M-16 rifle, it said at the time.
He had been accused of orchestrating several attacks on regime forces, including the brazen shooting on a commuter train in Rangoon in August that killed five policemen.
A hip-hop pioneer in Myanmar whose subversive rhymes irked the previous junta, he was jailed in 2008 for membership in an illegal organisation and possession of foreign currency.
He was elected to parliament from Suu Kyi’s NLD in the 2015 elections that ushered in a transition to civilian rule.
Kyaw Min Yu, who rose to prominence during Myanmar’s 1988 student uprising was arrested in an overnight raid in October.
Part of the so-called 88 Generation movement that challenged Myanmar’s previous military government, the junta issued an arrest warrant for him last year, alleging he had incited unrest with his social media posts.
Suu Kyi is facing a raft of criminal and corruption charges - including violating the country’s official secrets laws - and if convicted of all of them could face sentences tallying more than 100 years of prison.
She has already been sentenced to six years for illegally importing and possessing walkie-talkies, flouting COVID rules and incitement against the military.
Before the coup, she was on the cusp of beginning another five-year term as the country’s de facto leader after the NLD won a landslide in November 2020 polls.
Since the coup, many of her political allies have been arrested, with one chief minister sentenced to 75 years in jail.