Rebels from the Karen ethnic minority have issued a plea to Burma's military to stop an offensive that has forced thousands of people to flee villages in eastern Burma. This comes a day before a senior United Nations official is to hold talks with Burma's military leaders.

The Karen National Union issued a statement Wednesday calling on Burma's military junta - also known as the SPDC - to stop attacking Karen villages in the east, to withdraw troops from the area and to resume peace talks.

Colonel Ner Dah Mya

Colonel Ner Dah Mya, spokesman for the KNU, says the situation in eastern Burma is "intense" and a two-year-old informal cease-fire is no longer working.

"The KNU leadership, they're tired of the so-called gentleman's agreement cease-fire, so I think this [statement] is a kind of a warning to the SPDC," he said.

He accuses the military of burning villages, torturing people and displacing thousands of Karen.

The government says the offensive is in response to the KNU's increased "disruptive acts" - including bombings and planting mines on rail lines.

The international community has already condemned Burma's offensive. On Tuesday, several United Nations human rights experts, including human rights envoy to Burma Paulo Sergio Pinheiro, called on Burma to end the military operations. U.S. lawmakers also denounced the violence.

Thursday, United Nations Undersecretary-General Ibrahim Gambari arrives in Burma, where he will try to convince the ruling military to hasten democratic reforms and national reconciliation.

This is the first high-level visit by a U.N. envoy to Burma in two years. Similar efforts by Asian diplomats, have, however, failed to put pressure on the regime, which continues to detain members of the pro-democracy opposition.

There are some seven million Karen in Burma and they have one of the largest armed insurgencies in the country. The KNU has been fighting for autonomy for nearly six decades. It one of about 20 minority groups that have fought the government since Burma won independence in 1948.

In recent years, the government reached cease-fire agreements with 17 other ethnic minority rebel groups in Burma, but talks with the KNU failed in 2004.

Decades of fighting have forced thousands of Karen to flee to neighboring Thailand. The United States earlier this month waived provisions of anti-terror laws to allow some 9,000 ethnic Karen who fled Burma to be considered for political asylum.