By David Lawder

WASHINGTON (Reuters) - The Trump administration on Tuesday raised the stakes in a growing trade showdown with China, announcing 25 percent tariffs on some 1,300 industrial technology, transport and medical products to try to force changes in Beijing's intellectual property practices.

The U.S. Trade Representative's office unveiled a list of mainly non-consumer products representing about $50 billion of estimated 2018 imports that would nonetheless hit supply chains for many U.S. manufacturers. The list ranges from chemicals to TV sets, motor vehicles and electronic components.

Publication of the tariff lists starts a public comment and consultation period expected to last around two months, after which USTR said it would issue a "final determination" on the product list. It has scheduled a May 15 public hearing on the tariffs.

The announcement drew a swift threat of retaliation from the Chinese embassy in Washington.

"As the Chinese saying goes, it is only polite to reciprocate. The Chinese side will resort to the WTO dispute settlement mechanism and take corresponding measures of equal scale and strength against U.S. products in accordance with Chinese law," the embassy said in a statement.

The USTR target list follows China's imposition of tariffs on $3 billion worth of U.S. fruits, nuts, pork and wine to protest new U.S. steel and aluminum tariffs imposed last month by U.S. President Donald Trump.

The standoff between the world's two largest economies has sparked market fears that they could spiral into a trade war that could crush global growth.

CELLPHONES, COMPUTERS OFF LIST

The USTR tariff list conspicuously excluded many consumer electronics products such as cellphones and laptop computers assembled in China and also did not include clothing and footwear, drawing a sigh of relief from retailers who had feared higher costs for American consumers.

It did include Chinese-made flat-panel television sets and many electronic components, including light-emitting diodes increasingly used in lighting products. It also targeted vehicles such as motorcycles and electric cars, aircraft parts and electrical gear.

USTR Robert Lighthizer had said the tariff list was developed using a computer algorithm designed to choose products that would inflict maximum pain on Chinese exporters, but limit the damage to U.S. consumers.

The largest categories of U.S. imports from China were communications equipment, totaling $78 billion in 2017, with computer equipment second at $58.6 billion, according to U.S. Census data compiled by the Congressional Research Service.