A Myanmar ethnic rebel group has captured a military regional command in Rakhine state, it said, in what would be a major blow to the junta.

The Arakan Army had "completely captured" the western regional command at Ann on Friday after weeks of fighting, the group said in a statement on its Telegram channel.

Ann would be the second regional military command to fall to ethnic rebels in five months and a huge blow to the military.

Myanmar's military has 14 regional commands across the country with many of them currently fighting established ethnic rebel groups or newer "People's Defense Forces" that have sprung up to battle the military's 2021 coup.

Fighting has rocked Rakhine state since the AA attacked security forces in November last year, ending a ceasefire that had largely held since the putsch.

AA fighters have seized swathes of territory in the state that is home to China- and India-backed port projects and all but cut off state capital Sittwe.

The AA posted photos of a man whom it said was the Ann deputy regional commander, in the custody of its fighters.

AFP was unable to confirm that information and has contacted the AA's spokesperson for comment.

AFP was unable to reach people on the ground around Ann where internet and phone services are patchy.

In decades of on-off fighting since independence from Britain in 1948 the military had never lost a regional military command until last August, when the Myanmar National Democratic Alliance Army captured the northeastern command in Lashio in Shan state.

Myanmar's borderlands are home to myriad ethnic armed groups who have battled the military since independence for autonomy and control of lucrative resources.

Last month the U.N. warned Rakhine state was heading towards famine, as ongoing clashes squeeze commerce and agricultural production.

"Rakhine's economy has stopped functioning," the report from the U.N. Development Program said, projecting "famine conditions by mid-2025" if current levels of food insecurity were left unaddressed.