* U.N. says Uganda should try rebel commander
* Internet video spurs international hunt for LRA leader
By Elias Biryabarema
NAIROBI, May 22 (Reuters) - Uganda's chief prosecutor on Tuesday appeared to rule out any amnesty for Lord's Resistance Army commander Caesar Achellam, captured this month.
The Ugandan army's detention of Achellam, one of the LRA's top five members, has raised hopes it is closer to catching Joseph Kony, the rebel leader accused of war crimes for his group's near three-decade campaign of child abductions, rape and mutilation.
Richard Butera, Uganda's director of public prosecutions, said in a statement Achellam would be investigated and if found to belong to upper echelons for the LRA command, would be ineligible for pardon.
"It must also be noted that senior LRA officers involved in gross human rights violations do not benefit from amnesty because of their seniority in command and control," Butera said in the statement.
"If Achellam falls in that category, the issue will be assessed on evidence available."
Since Uganda passed its Amnesty Act in 2000, some 13,000 former LRA fighters have been pardoned, including many captured in battle.
The International Criminal Court at The Hague has issued arrest warrants for Kony and his top commanders for several counts of crimes against humanity and war crimes, although Achellam is not among those charged by the ICC.
Kony is accused of abducting children to use as fighters and sex slaves and is said to have a fondness for hacking off limbs.
A 30-minute YouTube video by California-based film-maker Jason Russell calling for the arrest of Kony swept across the Internet in March, attracting tens of millions of views, bringing the LRA's atrocities to the attention of many people previously unaware of the group's existence.
Late last year the United States deployed 100 special forces troops to help a 5000-strong African Union-mandated regional force hunting for Kony.
The prosecutor's statement followed comments by the chief legal adviser to the Uganda Amnesty Commission, Nathan Twinomugisha, who said Achellam was eligible to apply for amnesty and that his case would be considered as soon as he did so.
The U.N. Secretary-General's representative for Children and Armed Conflict, Radhika Coomaraswamy, has also called for Achellam's prosecution, describing him as "one of the worst perpetrators of child rights violations".
"The prosecution of the case will be taken on its merit and on the basis of evidence available," Butera said. (Reporting by Elias Biryabarema; Editing by George Obulutsa and Andrew Roche)