TOKYO, Feb 3 (Reuters) - Japanese shares tumbled on

Monday, led by automakers, after U.S. President Donald Trump

imposed tariffs on Canada, Mexico and China over the weekend,

raising worries that Japanese exports may also become a target.

The Nikkei had declined 2.1% to 38,742.33 by 0009

GMT, while the broader Topix was down 1.95% to 2,734.19.

Toyota Motor ( TM ) lost 4% and Honda Motor ( HMC ) lost

6%.

All of the Tokyo Stock Exchange's 33 industry sub-indexes

fell. The automaker index tumbled 4.8% to become the

worst performer.

The White House said the United States would impose 25%

tariffs on Canada and Mexico, and 10% on China.

Canada and Mexico immediately vowed retaliatory measures,

and China said it would challenge Trump's levies at the World

Trade Organization.

Game maker Konami Group ( KNAMF ) jumped 6% to become the

biggest support to the Nikkei.

(Reporting by Junko Fujita; Editing by Subhranshu Sahu)