The price of oil has hit its highest level for a month in response to the US military’s missile attack on a Syrian government airbase.
The price of Brent crude surged above $56 a barrel before easing slightly.
Syria has limited oil production, but its location in the Middle East and alliances with big oil producers raised worries about a spreading conflict that could disrupt crude shipments.
European stock markets, which open shortly, are expected to show falls.
Other asset classes seen as havens in times of trouble also made gains. Gold prices were up 1.25% at $1,253.75 an ounce.
The dollar’s performance was mixed, falling slightly against the dollar, sterling and yen, but holding its value against many other currencies.