Asian stock indices opened the fourth session of the week lower amid concerns in Korea after reports of North Korean shots that killed a South Korean official, the first incident of its kind since July 2008.
Earlier New Zealand data showed a trade deficit of 353 million New Zealand dollars, compared to a 447 million surplus in July.
Fed Chair Jerome Powell will present the second part of his Congressional testimony alongside US Treasury Secretary Steven Mnuchin.
Federal Reserve Chairman Jerome Powell said in a hearing before the US House that the Congress should pump extra stimulus to small firms to help ease the coronavirus impact.
Japan's TOPEX fell 0.67%, while Nikkei 225 fell 0.75% to 23,171.
China's CSI 300 declined 1.63%, while Shanghai lost 1.46% to 3,231.
Hong Kong's Hang Seng fell 1.78% to 23,319, while South Korea's KOSPI declined 1.72% to 2,293.
New Zealand's NZX 50 inched down 0.18%, while Australia's S&P/ASX 200 tumbled 0.96% to 5,867.