Foreign Ministry spokesman Hong Lei speaks at a press conference on March 16, 2015. [Photo: The Ministry of Foreign Affairs]

A China-Myanmar joint investigation is now underway following a bombing incident in a village in China's Yunnan Province on Friday.

A bomb dropped by a Myanmar warplane hit a sugarcane field in the border city of Lincang, killing five people and injuring eight others working there.

Foreign Ministry spokesman Hong Lei says China has lodged a solemn representation with authorities in Myanmar.

"The Myanmar Government says it feels sad about causing Chinese casualties in the incident, and they will conduct a serious investigation and deal with the incident properly. Yesterday, a Myanmar delegation arrived at the border area to start the joint investigation with China. "

The Vice Chairman of China's Central Military Commission has urged Myanmar to punish the perpetrators and apologize to and compensate the families of the victims.

The government of Myanmar has been locked in a battle with the Kokang ethnic minority in the northeast of the country since late last year.

Regional unrest has seen thousands of people from Myanmar cross over the border into China to seek refuge.