YANGON - Myanmar's army has captured a key strategic outpost in an escalating conflict in northern Kachin state, rebels said on Saturday.
The report came as the Myanmar government issued a rebuke to the United States for expressing its concerns about the fighting.
Bloody unrest has continued despite a government announcement of a unilateral ceasefire earlier this month, with fighting edging closer to the rebels' headquarters in the busy town of Laiza on the Chinese border.
KIA soldiers patrol in downtown Laiza in northeastern Myanmar earlier this month. (AP Photo)
The Myanmar Foreign Ministry said a US embassy statement, which was issued on Thursday and said the US "strongly opposes the ongoing fighting", had implied the army was the sole aggressor.
Myanmar said the US release "could cause misunderstanding in the international community".
Tens of thousands of people have been displaced in Kachin state since June 2011, when a 17-year ceasefire between the government and the Kachin Independence Army (KIA) broke down. The conflict has resulted in civilian casualties, although the exact number killed is unknown.
The KIA said a major strategic post had fallen to the Myanmar military on Saturday after it came under heavy artillery fire from multiple directions.
"That was the reason it collapsed. Finally we have to abandon that area, that mountain," James Lum Dau, the Thailand-based spokesman for the KIA's political wing, told AFP.
He said it was not clear whether the fighting would now move further toward Laiza - where thousands of civilians are thought to be taking shelter - but vowed that if "Laiza falls, [it]) does not mean KIA falls, absolutely".
Some civilians had already started to move, he added, but was unable to give further details.
Beijing this week urged an end to the fighting after Vice Foreign Minister Fu Ying visited Myanmar for talks with President Thein Sein. China's Foreign Ministry spokesman Hong Lei said the pair had agreed to maintain peace and stability on their shared border.
Chinese state-run media has reported that China's Yunnan province is planning camps for 10,000 people in case large numbers flee across the frontier.
Myanmar's government has reached tentative ceasefires with a number of ethnic rebel groups since taking power in early 2011 at the end of decades of military rule. But several rounds of talks with the Kachin have failed to bear fruit.
The rebels, who are fighting for greater autonomy, say any negotiations should also address their demands for more political rights.