Oil prices have jumped on concerns that the situation in Israel and Gaza could disrupt output from the Middle East.
Brent crude, the international benchmark, climbed by $2.25 a barrel to $86.83, while US prices also rose.
Israel and Palestinian territories are not oil producers but the Middle Eastern region accounts for almost a third of global supply.
Hamas's assault on Israel was the biggest escalation between the two sides for decades.
Western nations condemned the attacks. A spokesperson for Hamas, the Palestinian militant group, told the BBC that the group had direct backing for the move from Iran - one of the world's largest oil producers.
Welcome to the Wall Street Casino
Very little of the "value" in the stock market is based directly on the company's current products and services.
Angry sad noises. Yeah, I know. But I needed to rant about it anyways. There's so much wrong with the world and I can change nothing