Stocks fell Monday in Tokyo after conflict in the Middle East escalated over the weekend and the price of oil jumped, while the yen also weakened as traders and investors evaluated its safe-haven status in the current environment.

Politicians and economists cautioned that, while stable for now, the supply of oil could be affected if the clash becomes prolonged.

The Nikkei 225 stock average dropped about 2% at the open, and finished the day down 1.35%. Japanese government bonds strengthened slightly, and the country’s currency was volatile at the open and weakened to near ¥157 to the dollar in the afternoon.