The White House has announced plans to negotiate separate trade deals with Britain, the European Union and Japan.

We are committed to concluding these negotiations with timely and substantive results for American workers, farmers, ranchers and businesses, U.S. Trade Representative Robert Lighthizer said Tuesday.

He added that the White House wanted to "address both tariff and non-tariff barriers and to achieve fairer and more balanced trade."

As required by law, Lighthizer sent three separate letters to Congress announcing the intention to open trade talks.

He wrote that the negotiations with Britain would begin "as soon as it’s ready" after Britain’s expected exit from the European Union on March 29.

Lighthizer called the economic partnership between the U.S. and EU the "largest and most complex"in the world, noting the U.S. has a $151 billion trade deficit with the EU

Writing about Japan, Lighthizer said it is "an important but still often underperforming market for U.S. exporters of goods," noting that Washington also has a large trade deficit with Tokyo.

The top Democrat on the Senate Finance Committee, Oregon’s Ron Wyden, cautioned the administration against making what he called "quick, partial deals."

The administration must take the time to tackle trade barriers comprehensively, including using this opportunity to set a high bar in areas like labor rights, environmental protection and digital trade, he said.

President Donald Trump imposed tariffs on European steel and aluminum exports earlier this year and has threatened more tariffs on cars as a reaction to what he said were unfair deals that put the U.S. at a disadvantage.