By Justin Dralaze

KAMPALA (Reuters) - Residents and rights groups said U.S. troops being sent to Uganda would give a fresh impetus in the fight against Lord's Resistance Army rebels accused of murder and kidnapping children and capturing their leader.

The rebel group, which has waged a brutal insurgency for nearly 20 years, was ejected from northern Uganda in 2005 and has since roamed remote jungle straddling the borders of Sudan, Democratic Republic of Congo and Central African Republic.

Friday, President Barack Obama said he was sending about 100 troops to help and advise government forces fighting the LRA.

Obama -- who has denounced the LRA as an "affront to human dignity" -- said the troops would serve as trainers and advisers in the efforts to hunt down rebel leader Joseph Kony and would not be involved in combat except in self-defense.

"I think it is a good move because ... this will be a supplement to enforce the Ugandan UPDF (Uganda People Defense Forces) to make sure that Kony is put totally down and he faces justice for the crimes he has committed," Medie Sebuliba, a Kampala resident, said.

The LRA is known for chilling violence including hacking body parts off victims, the abduction of young boys to fight and young girls to be used as sex slaves.

Attempts to negotiate peace failed in 2008 after Kony, who is wanted by the International Criminal Court, refused to sign a deal to bring an end to the killing.

The arrival of the U.S. troops could make a real difference, said Friar Benoit Kinalegu, a civil society worker who follows LRA activity in Congo's northern province of Orientale.

"The biggest problem is not the number of troops on the ground, the biggest problem is the co-ordination of military intelligence," he told Reuters by telephone.

The LRA are still launching sporadic attacks in Congo's semi-arid north, but with Kony rumored to be in CAR and the Congolese troops receiving training from the U.S. military, the situation is improving, he said.

Although the group is thought to number just a few hundred, its mobility and the difficulties of the terrain have made them difficult to tackle.

Kinalegu says he is hopeful that more engagement from the United States and better planning could bring an end to the LRA threat.

"It's been a wish of mine for a long time," he added.

Kony is from the Acholi ethnic group, which has borne the brunt of the LRA insurgency and welcomed the U.S. move.

"We the people of Acholi who have been the victims of this war, we have clearly stated that we don't condone impunity, we don't support activities of rebellion by Kony," chairwoman of the Acholi Parliamentary Group Beatrice Atim, told Reuters.

(Additional reporting by Jonny Hogg in Kinshasa; Writing and editing by George Obulutsa)