By DENIS D. GRAY, Associated Press Writer Thu Apr 27, 12:46 AM ET

BANGKOK, Thailand - Myanmar troops waging their biggest military offensive in almost a decade have uprooted more than 11,000 ethnic minority civilians in a campaign punctuated by torture, killings and the burning of villages, according to reports from inside the country and Thailand.

The campaign by government troops in eastern Myanmar to suppress a decades-old insurgency among the Karen people began in November. But it has intensified in the past month, according to reports from the Free Burma Rangers, a group of Westerners and ethnic minority volunteers who provide aid to displaced people in the country formerly known as Burma.

Scores of villages have been abandoned and their inhabitants forced to flee into jungles. Some 11,000 people have fled their homes due to the onslaught, the Free Burma Rangers said. About 1,500 refugees have fled across the border to Thailand, and aid officials fear others will follow in coming months to swell the more than 140,000 already in Thai refugee camps.

Jack Dunford, executive director of the key frontier aid agency Thailand Burma Border Consortium, confirmed the influx, saying the refugees from Myanmar’s Karen State have arrived with "stories of increased (junta) troop activity, widespread destruction of villages and crops, and human rights abuses."

The military-run government has denied any human rights violations against ethnic minority groups, including the Karen, which it blames for recent bombings.

"There is no offensive against the Karen National Union but security measures have been taken and cleaning-up operations are being conducted in some areas where (KNU) terrorists are believed to be hiding," Information Minister Brig. Gen. Kyaw Hsan told reporters in the former capital of Yangon earlier this month, referring to the main Karen rebel group.

U.S. lawmakers called on the U.N. Security Council to take urgent action against the country’s ruling junta in response to the offensive.

Rep. Tom Lantos, the top Democrat on the U.S. House International Relations Committee, said in a statement Wednesday that the attacks were a "deadly escalation of what is already one of the world’s most serious humanitarian disasters."

He called on the Security Council to pass a binding resolution aimed at stopping the violence.

"The longer the Security Council waits, the more villages will be destroyed and more people will die," he said.

Another congressman, Rep. Joe Pitts, R-Pa., said in a statement the latest reports suggest the junta was actively hunting down more than 2,000 of the displaced. "The thugs of Rangoon are on a violent rampage," he said, referring to the former name of Yangon.

On Wednesday, Myanmar’s ruling military junta threatened to dissolve the pro-democracy party of Nobel Peace Prize laureate Aung San Suu Kyi for alleged links with illegal organizations - a reference to Thailand-based opposition groups, which the regime regularly blames for bombings and planning attacks.

The NLD won a landslide election in 1990, but the military refused to cede power and has kept Suu Kyi under house arrest for about 10 of the last 17 years and sent many of her followers to jail.

"The government has enough evidence to declare the NLD (National League for Democracy) as an unlawful association for its links with terrorist groups and exiled dissident organizations, but the government has not done so for various reasons," said Kyaw Hsan.

The United States and European Union have slapped sanctions on the junta for its poor human rights record and failure to release Suu Kyi.

Analysts say the scale of the recent attacks is the largest since a major offensive against the Karen in 1997 and the KNU fears it may continue through this year’s rainy season which begins around May. In the past, military operations were restricted to the dry season when movement through the rugged, malarial border region is easier.

"They don’t want the KNU near their new capital," said KNU General-Secretary Mahnshar Laphan, echoing some analysts who say the military is trying to secure the hinterland east of Pyinmana, which was recently established as the new capital.

He said the Karen were ready to restart peace talks that were broken off in 2004, but the offensive showed that "they don’t accept dialogue."

Myanmar’s military regimes, which first came to power in 1962, have battled numerous ethnic minority insurgent groups seeking autonomy until a former junta member, Gen. Khin Nyunt, negotiated cease-fires with 17 of them. But his ouster in 2004 reinforced hard-liners within the ruling junta and "resulted in increasing hostility directed at ethnic minority groups," U.S.-based Human Rights Watch said in its 2006 report.

The KNU are the largest of the rebel organizations still facing off against the regime’s 500,000-member military.

The violence of recent years, largely ignored by the international community, has spawned an estimated 1 million internal refugees and accelerated an exodus to neighboring countries.

In one incident described in a recent Free Burma Rangers report, Myanmar soldiers killed Saw Maw Keh as he was carrying his 80-year-old mother up a steep hillside in western Karen State earlier this month. The two were gunned down at point-blank range by soldiers waiting at the top of a ridge near their village, which was being abandoned in the face of an attack.

His 9-year-old daughter also was shot but survived.

Nearby, a still unidentified villager was found with one of his eyes gouged out and his nose cut off, one of several incidents of torture that the group has documented with graphic photographs and video.

The group says the military is trying to separate the civilians from the guerrillas, destroying villages and food stocks to deprive the insurgents of any local support. After residents flee, the areas are mined to prevent return of the villagers who seek shelter in remote, inhospitable regions or flee to refugee camps along the Thai border, it says.