A Myanmar military air strike killed more than 30 people at a hospital, an on-site aid worker said Thursday, as the junta wages a withering offensive ahead of elections beginning this month.

The junta has increased air strikes year-on-year since the start of Myanmar's civil war, conflict monitors say, after snatching power in a 2021 putsch ending a decade-long democratic experiment.

The military has set polls starting 28 December -- touting the vote as an off-ramp to fighting -- but rebels have pledged to block it from territory they control, which the junta is battling to claw back.

A military jet bombed the general hospital of Mrauk-U in western Rakhine state, bordering Bangladesh, on Wednesday evening, said on-site aid worker Wai Hun Aung.