MANKATO, Minn. (AP) -

Drug agents in south central Minnesota say a new way of making methamphetamine has led to a resurgence of illegal labs.

Portable, mobile meth kitchens are easy for manufacturers to set up and use -- and difficult for drug enforcement agents to find and shut down.

Veteran drug agent Ginger Peterson is with the Minnesota River Valley Drug Task Force. Peterson tells KTOE radio drug agents have seen four to six meth labs so far this year. Three years ago there were none.

New laws passed in 2005 made it difficult for criminals to obtain the large quantities of pseudoephedrine needed to make meth. Peterson says the one-pot method is a "whole new ballgame." Meth can be made with only a few pseudoephedrine tablets in a 2-liter bottle in approximately 30 to 45 minutes.