Burmese President Thein Sein says he is trying to create conditions for peace talks with ethnic-minority Kachin rebels.

In a speech in Rangoon, Mr. Thein Sein said government forces are within an “arm's length” of the main Kachin Independence Army base in the town of Laiza, on the border with China. He said he has ordered troops not to attack the base as a show of good will.

A Thailand-based spokesman for the Kachin rebel group said Burmese troops raided a rebel position Sunday several kilometers from Laiza, despite a unilateral government cease-fire that was supposed to go into effect Saturday. The rebel official said the government offensive involved artillery and ground troops.

Mr. Thein Sein's government had no immediate comment on the rebel claim about the fighting near Laiza.

The Burmese president called Sunday for the Kachin Independence Army to return to the negotiating table as soon as possible to develop what he called a “sustainable peace.”

Burmese troops and Kachin rebels have been fighting since 2011, when a 17-year cease-fire broke down. It is the last active civil war in Burma, whose reformist government has reached cease-fire agreements with other ethnic minority rebel groups.

The fighting in Kachin state has displaced tens of thousands of people and overshadowed major political reforms introduced since Burma ended decades of military rule in 2011.