Paraguay grants immunity to US Troops?

This news (link to the Argentinean newspaper Clarín, in Spanish) has strucked me! I am actually really puzzled that this news hasn't really been more public. I just found out on the Argentinean newspaper almost by mistake. It's a real outrage!

Here is an excerpt from the NarcoSphere:

agreement approved by the Paraguayan Congress which will allow US troops into the country for an 18-month training and advisory mission from June 1, 2005 through December 31, 2006. The agreement grants full immunity from prosecution to all US personnel involved in the mission. Congress approved the agreement--apparently at the end of last year--with no debate and behind closed doors, and the public was largely unaware of it, according to SERPAJ Paraguay.