TOKYO, June 19 (Reuters) - The U.S. administration's

policy shift to introduce high tariffs will increase the

strategic importance of Nippon Steel's ( NISTF ) business

development in the U.S. market, the top Japanese steelmaker's

CEO, Eiji Hashimoto, said on Thursday.

Hashimoto was speaking at a press conference in Tokyo a day

after Nippon Steel ( NISTF ) closed its $14.9 billion acquisition of U.S.

Steel, confirming an unusual degree of power for

President Donald Trump after the Japanese company's 18-month

struggle to close the purchase.

The companies also disclosed details of a national security

agreement inked with the Trump administration, which gives the

president the authority to name a board member as well as a

non-economic golden share.

The measures represent an unusual level of control conceded

by the companies to the government to save the deal, after a

rocky path to approval spurred by high-level political

opposition.