The Nikkei Average turned negative, weighing on trading in the Tokyo market. South Korean stocks also extended their declines, with expectations that Samsung Electronics' earnings would fall short of forecasts weighing on the market. In after-hours US trading, the Nasdaq fell more than 1% at one point.
In Tokyo-hour trading, the Nikkei Average turned negative and closed at 63949.78 yen. The Korea Composite Stock Price Index also stood at 5835.39, down 177.05 points, with declines widening in both markets.
After-hours trading continued to reflect selling prompted by Alphabet's earnings in the US, with the Nasdaq trading more than 1% lower.
South Korean stocks fell amid speculation that profit at Samsung Electronics' semiconductor division had come in below market expectations, sending Samsung Electronics plunging 4%.
Market participants are focused on upcoming earnings and the outlook for the semiconductor sector.