Oil prices extended gains in late trading on Friday after Turkey's armed forces said they had taken power in the country, igniting concerns about potential disruptions to shipments along one of the world's busiest shipping routes.
Turkey's military said on Friday it had seized power, but the prime minister said the attempted coup would be put down.
If successful, the overthrow of President Tayyip Erdogan, who has ruled Turkey since 2003, would amount to one of the biggest shifts in power in the Middle East in years.
In the oil market, outages in Nigeria, Canada and South America have led to crude prices rallying from 12-year lows touched earlier in the year as a result of a massive glut. A potential military coup could mean further disruptions.
"The thing that everyone is very much focused on is what's going on with the Turkish Straits and how that is going to play out," Jamie Webster, fellow at Columbia's Center on Global Energy Policy said.
"So it would make sense for oil to jump up just a bit as the market waits for more real data."
The Turkish Straits, which includes the Bosphorus and Dardanelles waterways, divide Asia from Europe and are one of the world's busiest narrow strategic water channels, linking Russia's vital Black Sea oil ports to Europe and beyond.
About 3 million barrels of crude and petroleum products flowed through the straits each day in 2013, according to a report by the U.S. Energy Information Administration in December 2014.
U.S. crude extended gains to trade as high as $46.33 after settling at $45.95 a barrel on Friday. Brent crude rose to a high of $48.25 after ending the session at $47.61.
A military coup also raises concerns about an impact to the Kirkuk-Ceyhan pipeline, which runs from Iraq's Kirkuk oil fields to the Mediterranean port of Ceyhan in Turkey.