UPDATE 1-US, Canada working on heavy truck emissions rules

* Standards for heavy trucks to be released soon

* Announcement follows rules for light trucks, cars (Adds details, quotes)

OTTAWA, April 1 (Reuters) - The United States and Canada are working together on proposed emissions standards for heavy trucks, which should be released in the next few months, Canadian Environment Minister Jim Prentice said on Thursday.

Prentice was speaking at a news conference to announce the two nations would bring in tougher new emissions standards for cars and light trucks.

"The whole subject of heavy trucks -- the kinds of tractor-trailer units you'd seen on the highway, for example -- is the subject of different discussions that are going on with the (U.S.) Environmental Protection Agency," he said.

"We have a working group that is focused on that. We anticipate that ,later this spring, we will be in a position to put forward the standard for heavy trucks."

Major truck manufacturers include Germany's Daimler (DAIGn.DE), maker of the Freightliner, and Sweden's Volvo (VOLVb.ST), which produces vehicles under the Volvo and Mack brands.

Other makers include as Paccar Inc (PCAR.O), which produces the Kenworth and Peterbilt brands, as well as Sweden's Scania (SCVb.ST) and MAN (MANG.DE) of Germany. (Reporting by David Ljunggren; editing by Rob Wilson)