TOKYO (AP) — Greece's foray into the unknown with its rejection of terms set by its international creditors is jolting markets as investors react to looming uncertainties.

Japan's Nikkei 225 stock index dropped 1.5 percent shortly after the market opened Monday, but was trading down 1.4 percent at 20,256.69 about a half-hour later. South Korea's Kospi declined 0.9 percent to 2,085.67.

Elsewhere, Australia's ASX S&P 200 fell 1.4 percent to 5,462.60 shortly after trading began early Monday, while New Zealand's benchmark slipped 0.6 percent to 5,808.75. Shares were expected to take a hit across the region and beyond.

With 97 percent of the votes counted, results showed 61 percent of Greek voters opted to reject the demand for further austerity measures, while 38 percent said "yes."

A summit of euro zone leaders was due Tuesday to discuss next steps. While Greece's economy is relatively small, the vote could result in it abandoning the euro if the country must issue its own currency to alleviate a cash crunch.