Myanmar's junta has executed four prisoners including a former lawmaker from Aung San Suu Kyi's party and a prominent activist, state media said Monday, in the country's first use of capital punishment in decades.

The four were executed for leading "brutal and inhumane terror acts", the Global New Light of Myanmar newspaper said.

The paper said the executions were carried out "under the prison's procedure" without saying when or how the men were killed.

The junta has sentenced dozens of anti-coup activists to death as part of its crackdown on dissent after seizing power last year, but Myanmar had not carried out an execution for decades.

Phyo Zeya Thaw, a former lawmaker from Suu Kyi's National League for Democracy (NLD) who was arrested in November, was sentenced to death in January for offences under anti-terrorism laws.

Democracy activist Kyaw Min Yu -- better known as "Jimmy" -- received the same sentence from the military tribunal.

Two other men were sentenced to death for killing a woman they alleged was an informer for the junta in Yangon.

Diplomatic condemnation

The junta was heavily criticised by international powers last month when it announced its intention to carry out the executions.

United Nations Secretary-General Antonio Guterres condemned the junta's decision, calling it "a blatant violation to the right to life, liberty and security of person".

UN rights experts said that if the executions went ahead -- for the first time in Myanmar since 1988 -- it could mark the start of a spate of hangings.

The experts said that under the junta's martial law provisions, the death penalty could be given for 23 "vague and broadly defined offences" -- which in practice could include any criticism of the military.

Myanmar expert Richard Horsey of the International Crisis Group (ICG) said on Twitter that the executions were "an outrageous act. And one that will create political shockwaves, now and for a long time to come".

Phyo Zeya Thaw had been accused of orchestrating several attacks on regime forces, including a gun attack on a commuter train in Yangon in August that killed five policemen.

A hip-hop pioneer 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 representing Aung San Suu Kyi's NLD in the 2015 elections, which ushered in a transition to civilian rule.

The country's military alleged voter fraud during elections in 2020 -- which the NLD won by a landslide -- as justification for its coup on February 1 last year.

Suu Kyi has been detained since then and faces a slew of charges in a junta court that could see her face a prison sentence of more than 150 years.

Kyaw Min Yu, who rose to prominence during Myanmar's 1988 student uprising against the country's previous military regime, was arrested in an overnight raid in October.