Oil prices climbed more than 1 percent on Thursday due to a threatened strike in Nigeria and as traders covered shorts after sharp losses the previous day.
One of Nigeria's main oil unions threatened to go on strike from Dec. 18 over what it said was a "mass sacking of workers." The country is Africa's top oil exporter.
"Short covering in the market, together with the threat of a strike by Nigeria's key oil union, has provided some support to oil prices in today's session," said Abhishek Kumar, senior energy analyst at Interfax Energy's Global Gas Analytics in London.
U.S. West Texas Intermediate (WTI) crude futures ended Thursday's session 73 cents, or 1.3 percent, higher at $56.69 a barrel. Brent crude futures, the international benchmark for oil prices, were up 88 cents, or 1.4 percent, at $62.10 a barrel at 2:27 p.m. ET (1927 GMT).