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.
Brent crude surged above $56 a barrel, but later fell back to just over $55.
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 markets opened lower, but London’s FTSE 100 gained ground later.
It ended the day 0.6% higher at 7,349 points. The Cac in Paris also closed higher, up 0.3%, but Frankfurt’s Dax was 5 points lower.
Other asset classes seen as havens in times of trouble made gains. Gold prices were up 1.1% at $1,266.45 an ounce on Friday afternoon.
The dollar’s performance was mixed, falling slightly against the yen.
However, it rose modestly against sterling, the euro and the Swiss franc.
Earlier in Asian markets, energy shares rose as a result of the airstrike, giving a boost to Japan’s Nikkei index, which closed up 0.36% at 18,664.
Analysts said the market impact of the attacks was likely to be short-lived, since the US had described it as a “one-off”.
“It was a knee-jerk reaction because markets are starting to come back a little, as it doesn’t seem like there will be further retaliation coming,” said Christoffer Moltke-Leth at Saxo Capital Markets in Singapore.