* Topix volume and turnover subdued
* U.S. political woes, U.S.-South Korea drills keep markets jittery
* Nippon Yusen outperforms on report it will offer payouts this FY
TOKYO, Aug 21 (Reuters) - Japanese stocks fell to a fresh 3-1/2-month low on Monday as global investors remained cautious amid worries over whether the Trump administration will be able to implement growth boosting measures.
The Nikkei ended down 0.4 percent at 19,393.13 points, its lowest closing level since May 1.
The dollar was at 109.20 yen, not far from Friday's four-month low of 108.605.
The broader Topix dropped 0.1 percent to 1,595.19, the lowest closing level since June 15. Volume hit a three-month low of 1.40 billion shares, while turnover dropped to a two-month low of 1.753 trillion yen.
In the latest shakeup, the White House said U.S. President Donald Trump on Friday fired chief strategist Steve Bannon, known as an economic nationalist and an advocate of "America First" policies. Critics have accused him of harboring anti-Semitic and white nationalist sentiments.
"There is something every day that's worrying the market... People are risk averse as various risks are coming from the United States now," said Hikaru Sato, a senior technical analyst at Daiwa Securities.
He also added that the market remains jittery as the United States and South Korea will go ahead with joint military drills this week.
Financial stocks such as banks, securities and insurers underperformed, with Mitsubishi UFJ Financial Group dropping 1.3 percent, Nomura Holdings sliding 1.9 percent and Dai-ichi Life Holdings falling 1.6 percent.
Bucking the weaker broader trend, mining shares rose, with Inpex Corp advancing 1.5 percent and Japan Petroleum Exploration Co adding 0.6 percent after oil prices held on to Friday's big gains.
Japan's major maritime shipper Nippon Yusen KK soared 1.9 percent after the Nikkei business daily reported that the company is preparing to resume dividend payments for the current fiscal year, after no payouts were offered last year.
The company secured cash by transferring funds from capital surplus to retained earnings in June, the Nikkei said. (Editing by Kim Coghill)