TOKYO (AP) -- Japan's Prime Minister Shigeru Ishiba said Tuesday his government is making last ditch efforts to get U.S. President Donald Trump to exclude his country from an increase in auto tariffs due to take effect from Wednesday.

Ishiba told reporters he is willing to fly to Washington to negotiate directly with Trump. The U.S. will begin collecting 25% tariffs on auto imports on Thursday, with taxes on fully-imported cars kicking in at midnight, U.S. time. The tariffs are set to expand to applicable auto parts in weeks to come.

So far, Japan has not managed to win exemptions from the tariffs hitlist despite its status as the biggest U.S. ally in Asia. Japan has stepped up cooperation with other countries that also are being affected. Japanese Trade Ninister Yoji Muto flew to Seoul to meet with his counterparts from South Korea and China and agreed to promote a free and fair trade and investment, saying Trump's trade policies are fueling protectionism.

The higher tariffs are a worry for Japan and major automakers like Toyota Motor Corp. and Honda Motor Co. Their exports to the United States are a major driver for the Japanese economy. A quarterly survey by the Bank of Japan released Tuesday showed business sentiment among large manufacturers worsened in the past quarter for the first time in a year.

"I don't mind going to Washington, if necessary," Ishiba said.

He said officials from all related ministries, including foreign, trade and finance, are working "day and night," to negotiate with their U.S. counterparts to resolve the issue. "When I see the overall picture and judge that it is appropriate for me to go, I must do so without hesitation, he said.

If the tariffs are imposed, he said the government will do what it must to minimize their impact on Japanese industries and jobs.

As short-term measures, the government plans to set up 1,000 consultation windows across the country to respond to concerns of small to medium-size auto parts makers and other manufacturers that would be affected by the U.S. tariff increase.

In case of damage to actual businesses, the government will do its utmost to support cash-strapped business owners, Ishiba said.