BANGKOK (AFP) -- Ethnic Karen rebels Wednesday issued a new plea for cease-fire talks with Myanmar's military rulers, saying the plight of their people was increasingly desperate in the face of a bloody offensive.

The Karen National Union, the oldest and largest rebel group battling Myanmar's junta, said the violence had exacted a crushing toll on villages in eastern Myanmar with some 11,000 people forced from their homes.

Advancing Myanmar forces had committed a litany of abuses against civilians in their path, including rape, torture, forced labor and burning of entire villages, the KNU said in a statement.

"The KNU solemnly call upon the SPDC military regime to immediately stop its current military operations and withdraw its operational troops, hold talks seriously with the KNU, abandon its policy of total obliteration and resolve the country's problems by political means," the rebels said.

The junta, which calls itself the State Peace and Development Council (SPDC), launched the offensive in February.

Fighting during the dry months is normal in Myanmar, but the KNU said the military had stocked its front-line positions to press ahead even amid the seasonal rains that make travel difficult.

"The KNU strongly protest and condemn the SPDC's wicked act of increasing military operations against us, instead of working toward nationwide ceasefire," the statement said.

The military has reached cease-fires with 17 other ethnic armed groups, but talks with the KNU fell apart two years ago and have yet to resume.

The two sides had reached a "gentlemen's agreement" to stop fighting until a cease-fire was hammered out.

Both sides insist they remain open to talks, even as the military presses ahead with its offensive.

Although the KNU once controlled a vast stretch of Karen state, the Myanmar military has made steady gains in recent years, leaving the rebels with little more than a string of bases mainly along the Thai border.

Myanmar has faced mounting pressure to halt its offensive, with rights groups denouncing its tactics.

Six United Nations human rights experts on Tuesday called on the military to end the fighting because of its brutal impact on thousands of civilians.

The UN's top political official, Ibrahim Gambari, is due to arrive in Yangon on Thursday in the world body's highest-level contact with the reclusive junta in more than two years.