Thai armored cars patrolled the town of Mae Sot on Wednesday as the deep boom of artillery thundered across the border in Myanmar, where the junta and an ethnic armed group fought for a second day near a vital trade hub.

Hundreds waited to enter Thailand at the immigration checkpoint in Mae Sot, many fleeing the newest round of fighting to test the junta's hold on power.

Thai soldiers took up positions underneath the friendship bridge linking the town with Myanmar trade hub Myawaddy, the silhouettes of their counterparts from the Myanmar army visible across the sparse 200 meters of dirt and dried river dividing the nations.