A Myanmar military offensive against ethnic rebels in the country's east has uprooted more than 10,000 people, a rights group says.

The Shan Human Rights Foundation (SHRF) has accused the army of bombing schools and Buddhist temples, firing on civilians, and raping women in Shan state, where armed groups have fought government forces for years.

Since October 6, the army has shelled six villages, shot and wounded three people, and fired on 17 villagers who are now missing, according to activists.

The group has documented eight cases of sexual violence since April, including a 32-year-old woman gang-raped by 10 soldiers on November 5 while her husband was tied up.

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"We are very concerned that there has been no public condemnation by the international community about these war crimes and these attacks on civilians," rights activist Charm Tong told the Thomson Reuters Foundation.

In 2010, the country's ruling military was replaced by an army-backed civilian government, and the country embarked on reforms towards elections that were held earlier this month. The vote saw opposition leader Aung San Suu Kyi's National League for Democracy win in a landslide.

Myanmar has fought ethnic groups in its borderlands off and on for decades, causing massive displacement within the country and forcing hundreds of thousands to seek refuge across the border in Thailand.

The Myanmar government did not respond to requests for comment about the fighting in Shan state.

US Assistant Secretary of State Daniel Russel, after talks this week with Myanmar's Armed Forces Chief Min Aung Hlaing, described the military operations and fighting in Shan and neighbouring Kachin state as "very worrisome".

"We have concerns about the humanitarian crisis that is generated by the fighting. We also have concerns that the fighting could set back the effort to build out a nationwide ceasefire to include non-signatories," Russel told Reuters in Yangon.

Source: Thomson Reuters Foundation