It said China’s Vice Foreign Minister Liu Zhenmin had lodged “solemn representations” to ambassador U Thit Linn Ohn over the incident earlier that day in Yunnan Province across the border from the Kokang special region.
The report said the four Chinese were working in a sugarcane field near the border city of Lincang when they were killed by the bomb, that also injured nine people.
Mr Liu had condemned the bombing and urged the Myanmar side to thoroughly investigate the incident and tell the Chinese side of the result, Xinhua reported.
He also urged Myanmar to punish the perpetrator and take immediate and effective measures to prevent a recurrence of such incidents and to safeguard the security and stability of border areas between the two countries, it said.
The Chinese foreign ministry said earlier this week that a stray shell from fighting in the Kokang region had damaged a house in China on March 8.
The fighting began on February 9 when a Kokang rebel group, the Myanmar National Democratic Alliance Army, launched a surprise attack aimed at capturing the regional capital, Laukkai.