Myanmar's junta will "annihilate" coup opponents, army chief Min Aung Hlaing said Sunday as the military staged a show of force on the anniversary of its bloodiest crackdown so far on democracy protests.

The Southeast Asian country has been in chaos since a putsch in February 2021, with more than 1,700 people killed in crackdowns on dissent, according to a local monitoring group.

Across the country "People's Defence Force" fighters -- often armed with homemade or rudimentary weapons -- clash regularly with junta troops, with some analysts suggesting the military has struggled to respond effectively to their hit-and-run tactics.

Fighting has also flared with more established ethnic rebel groups along the Thai and Chinese border.

Presiding over the annual parade that showcased tanks, truck-mounted missiles, artillery and troops on horseback, Min Aung Hlaing told some 8,000 assembled security personnel that the army would not let up.

The military will "no longer negotiate... and annihilate until the end" groups fighting to overturn its rule, he said ahead of the Armed Forces Day procession in army-built capital Naypyidaw.

Jets flew overhead trailing the yellow, red and green of the national flag, while state media showed women lining the streets leading to the parade ground to give flowers and place garlands on the marching soldiers.

In commercial hub Yangon around a dozen anti-junta flashmob protesters set off flares and shouted slogans, according to footage posted on social media. 

Others called on social media for residents to switch off their lights at home in a national "power strike" on Sunday evening.

- Bloodiest Day -
Armed Forces Day commemorates the start of local resistance to the Japanese occupation during World War II, and usually features a military parade attended by foreign officers and diplomats.

Last year, as new junta chief Min Aung Hlaing inspected the parade, troops brutalised those protesting the coup that had ousted Aung San Suu Kyi's government.

The violence was the bloodiest day so far in the military's crackdown on democracy rallies and left around 160 protesters dead, according to a local monitoring group, as well as sparking widespread international condemnation.

The junta has become increasingly isolated, with Cambodian strongman Hun Sen the only foreign leader to visit since the putsch.

On Sunday Min Aung Hlaing accused unnamed "foreign aggressors" of working against the military and called for the armed forces to remain united against "internal and external mischiefs."

Russia's vice defence minister -- a major arms supplier and ally -- had been due to attend this year's parade but was unable to because of his "country's affairs", junta spokesman Zaw Min Tun added.

In February a UN expert on Myanmar said Russia -- along with other major ally China -- was continuing to supply the military with weapons, including fighter jets and armoured vehicles. 

The United States and Britain on Friday announced new sanctions against Myanmar's army. 

The new measures came days after Washington said it has concluded that the country's military committed genocide against the mostly Muslim Rohingya minority.