Myanmar's air force is reported to have dropped a bomb in a field on Chinese territory, killing four civilians.
China in response sent fighter jets to their shared border in the Yunnan province.
Myanmar denied dropping the bomb and said Kokang rebels, who have been fighting the Burmese army, may have been behind the attack.
"It's possible that those fighting with us purposely created these attacks with the intent of causing misunderstanding between China and us," a Myanmar official told Reuters.
China's deputy foreign minister, Liu Zhenmin, summoned Myanmar's ambassador, Thit Linn Ohn, to complain about the bombing.
Clashes between Myanmar army and Kokang rebels continue, amidst human rights chief warning (25 Feb 2015)