It added that the military had to take action but exercised “maximum restraint” in the use of force. It also said the positions from which the military dislodged the Kachin were in uninhabited territory.
Fighting initially erupted in Kachin state in June 2011 after the KIA refused to abandon a strategic base near a hydropower plant that is a joint venture with a Chinese company.
The government last month delivered an ultimatum to the Kachin to clear a road by Christmas Day so it could supply its base. The Kachin rejected the ultimatum for fear of a government attack on their own outpost.
The Kachin have been reaching out for help from the international community.
A network of Kachin support groups on Thursday sent a letter to the Geneva-based International Committee of the Red Cross to take action against the “daily escalation of attacks” by the army and to protect the Kachin civilians.
It claimed the government was utilizing Chinese airspace for its offensive, and that the Kachin could not flee to safety because China had closed the border to them, while Myanmar's government blocked relief assistance.
In Beijing, Chinese Foreign Ministry spokeswoman Hua Chunying said Friday that during armed clashes between Myanmar government forces and Kachin rebels on the night of Dec. 30, three bombs landed in the Chinese border area but did not cause casualties.
Hua added that while the Chinese government regarded the fighting as Myanmar's internal affair, Beijing still hoped that the Myanmar government would address the issue through “peaceful negotiation with relevant parties.”
China is a key ally of Myanmar as the country's main aid donor and investor. But relations have cooled as Thein Sein's government has reached out to the West to help kick-start economic growth. Many Western nations have eased economic and political sanctions that were imposed against the previous military government for its repressive policies. But Kachin state's position on the Chinese border means Beijing can still exercise its influence over both sides.
The United States earlier said the use of air power in Kachin state is “extremely troubling.” On Thursday, State Department spokeswoman Victoria Nuland said the U.S. is seeking clarity on the situation following conflicting statements from Myanmar authorities, and is urging both the government and Kachin representatives to stop fighting.
“Our view is that all sides need to cease and desist and get into dialogue with each other,” she told a news briefing.