At least 30 people were killed Monday in a day of intense fighting between security forces and ethnic rebels on Myanmar's border with China, authorities said.

Five civilians, five police officers and at least 20 rebel fighters died after clashes broke out at Laukkai in the northeastern state of Shan, according to a statement by the office of Myanmar's civilian leader Aung San Suu Kyi.

"According to initial information, many innocent civilians including a primary school teacher... were killed because of attacks by the MNDAA armed group," said the statement on Facebook, referring to the acronym of the rebel group fighting Myanmar's military in the region.