The United States says it is concerned by violence between Burma's government and rebels in northern Kachin state, particularly by reports of human rights abuses in the area.

A State Department spokeswoman said Friday there are reports of casualties, rapes, and the displacement of thousands of local residents.

She called for an end to the fighting and said the violence underscores the need for dialogue among Burma's government, opposition, and ethnic minority groups.

The spokeswoman urged all authorities to ensure the safety and protection of people fleeing the conflict.

On Thursday, refugee aid workers said China is ordering hundreds of refugees who fled the fighting to return to Burma.

The aid workers said at least 2,000 villagers have been displaced by the Burmese offensive against rebels of the Kachin Independence Army, which began earlier this month.

Most have sought shelter along the Chinese border in hopes the army will not risk firing artillery so close to their northern neighbor.

China has denied it is turning back refugees at the border.

The Kachin Independence Army, like several other ethnic militias in Burma, signed a cease-fire agreement with the central government several years ago. But those agreements began to break down in 2009, when Burma demanded that the militia groups come under central authority and serve as part of a national border guard. That prompted some militias to resume fighting.