The Nikkei 225 has declined, with reports of the drop ranging from 556 to 721 yen, amid a surge in crude oil prices and concerns over Middle East tensions. Semiconductor buybacks are said to have cushioned the decline, but the market's reaction is mixed, with some reports indicating panic selling and others noting more cautious trading. The decline is also part of a broader trend affecting Asian markets, with other regional stocks, including those in Singapore, also falling.