Many of the country's gems, especially jade and rubies, come from the contested areas in Kachin State.
It points out that the Burmese government has never controlled much of the territory in Kachin state.
Troops continued a raid on rebels in Kachin state in the east over recent months, despite the president's orders to cease.
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Last month a crate was discovered in the Kachin state capital Myitkyina, but muddy water stopped an immediate identification of its contents.
It has told our correspondent that it wants the Burmese military to scale back its operations throughout Kachin state and not just around Laiza.
Because, for example, not only Kachins live in the Kachin state.
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"We note that the government did today admit that they have been using aerial weapons in Kachin state, " US State Department spokeswoman, Victoria Nuland, said on Wednesday.
Kyaw Ba, the tough former northern commander in Kachin State who is now Minister of Tourism, Tun Kyi has been reined in by the head of SLORC, Than Shwe.
No process of reform will succeed without national reconciliation. (Applause.) You now have a moment of remarkable opportunity to transform cease-fires into lasting settlements, and to pursue peace where conflicts still linger, including in Kachin State.
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The BBC's Jonah Fisher - who is travelling with Ms Amos in Burma - says that, while the country has seen dramatic reforms, Kachin state is a painful reminder of the complexity of the problems that still remain.
Yet, as if to illustrate just how hard this will be, fighting has worsened in Kachin state in the north, a result of an army offensive against the Kachin Independence Army (KIA) which has displaced 50, 000 people, some fleeing into China.
The war would probably drag on, robbing President Thein Sein of the peaceful new start he is promising his country, entrenching the power of the military in this strategic border area, and unnerving China, which sees Kachin state as a vital trade and energy corridor.
The Burmese government has acknowledged that the military carried out air attacks against rebel fighters in the northern state of Kachin.
The government has signed a series of fragile cease-fires with many of the insurgent groups, but some have already frayed, with clashes having recently erupted in Shan state and the Kachin still fighting the government.
Burma's army has, since June, been fighting both the Kachin Independence Army and the Shan State Army.
The Kachin Independence Army (KIA) has fought the Burmese state for 50 years.
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Thein Sein took office two years ago this month, and despite ushering in an era of reform, he has faced not only violence in Rakhine state, but an upsurge in fighting with ethnic Kachin rebels in the north and major protests at a northern copper mine where angry residents emboldened by promises of freedom of expression have come out to denounce land grabbing.
Thousands of Rohingya Muslims have been displaced by ethnic violence in western Burma's Rakhine state, while in recent months there has been conflict between ethnic Kachin fighters and the Burmese military in the north-east.
Burmese troops attacked a Kachin base just a few kilometres from Laiza, the biggest town controlled by rebels in the state, near the Chinese border.
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