The United States is expected to pursue setting higher standards to qualify for reduced tariffs in upcoming trade talks with Japan, such as by raising the percentage of auto parts to be made in either of the two countries, sources close to the matter said Monday.

The inclusion of such country of origin rules in a bilateral trade deal could serve as a blow to Japanese automakers, which export their vehicles partly made up of components supplied from countries such as China and Thailand, where labor costs are low.

According to the sources, negotiators will start off the first round of the talks, slated for April 15 to 16 in Washington, by narrowing down the scope of the negotiations. Rules of origin, customs procedures, food safety regulations, and safeguard measures are expected to be included.