The Senate on Thursday approved President Donald Trump's nomination of Tennessee businessman William Hagerty as U.S. ambassador to Japan.

Hagerty, 57, is expected to take up the post in August, according to a source familiar with Japan-U.S. relations.

He will serve in Tokyo at a time when the security environment in the Asia-Pacific region has become increasingly severe amid China's military buildup and territorial ambitions in the East and South China seas, as well as North Korea's development of nuclear-tipped ballistic missiles that could strike as far as the United States.

In light of Trump's calls for "fair" trade, Hagerty, who served as a key member of the Trump transition team, is expected to call for greater market access for U.S. products in Japan as part of an effort to reduce the U.S. trade deficit with the country.

The upper chamber of Congress voted 86 to 12 in favor of the new ambassador in a plenary session.

State Department spokeswoman Heather Nauert welcomed the Senate vote, saying, "We're looking forward to having him join Japan as our next U.S. ambassador."

"He spent a good deal of time over there. I know he's steeped in the issues," Nauert told a press briefing.

In a Senate confirmation hearing on May 18, Hagerty reaffirmed Washington's "ironclad" commitment to its alliance with Tokyo, calling it "the cornerstone of regional peace and security" and "a platform for global cooperation."

The ambassador-in-waiting underlined the United States' "unwavering" commitment to the defense of the Senkaku Islands, a group of East China Sea islets administered by Japan but claimed by China and Taiwan, in accordance with the Japan-U.S. security treaty.

Hagerty stressed the need for close coordination with Japan and trilaterally with South Korea in pressing North Korea "to abandon its unlawful nuclear, ballistic missile and proliferation programs."

On the economic front, Hagerty pledged to help increase U.S. exports to Japan in areas such as agriculture, defense and manufacturing including automobiles.

He added that U.S. exports of energy such as liquid natural gas to Japan could significantly cut into the trade deficit.

Hagerty built ties with Japan through a three-year posting to Tokyo from the late 1980s to early 1990s while working for the Boston Consulting Group, and in his work as commissioner of economic development for Tennessee from 2011 to 2015.

The new ambassador will succeed Caroline Kennedy, who served under President Barack Obama's administration before leaving Tokyo in January.