Ethnic Kachin rebels in northern Burma say government forces shelled the town they use as their headquarters, killing three civilians and wounding three others.

A member of the Kachin Independence Army said the attack on the town of Laiza, near Burma's northeast border with China occurred early Monday morning. He said one of those killed was a 15-year-old boy.

The Kachinland News, an independent media organization that reports news in ethnic Kachin areas, quoted a witness as saying shells fell in a residential area where about 40,000 displaced Kachins from other areas of Burma live with local residents.

The United States and the United Nations are urging the Burmese government to stop its campaign of strikes against rebels in Kachin state, where an escalation in violence is threatening the country's reform process.