The Southeast Asian country has been in turmoil since a coup last year ousted Aung San Suu Kyi's administration and sparked mass democracy protests and a deadly crackdown.

Foreign minister Wunna Maung Lwin left Myanmar on Thursday morning for a "work trip" to China at the invitation of Chinese Foreign Minister Wang Yi, the junta's information team said in a statement late Thursday.

It gave no details on his destination in China or how long the trip was scheduled to last.

China is a major ally of the junta and has refused to label the military's power grab a coup.

The junta is increasingly isolated on the international stage, with Cambodian strongman Hun Sen the only foreign leader to visit since the putsch.

Last month Wunna Maung Lwin was barred from attending a foreign minister's retreat of the Association of Southeast Asian Nations (ASEAN) regional bloc over a lack of progress in defusing post-coup violence.

But clashes have continued, with anti-junta groups battling regularly with the military.

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

More than 1,700 people have been killed in a military crackdown on dissent since the coup, according to a local monitoring group.

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.