Oil prices extended gains on Thursday, after having touched three-week highs the previous day on mounting supply tightness concerns.
Benchmark Brent crude futures edged up 0.4 percent to $101.58 per dollar, while WTI crude futures were up 0.2 percent at $95.03.
Russian crude exports have been on a downward trajectory this summer, failing to 4.6 million b/d in June and 4.2 million b/d in July, according to Rystad Energy estimates.
Saudi Arabia's warning that OPEC could cut output to correct a recent drop in oil futures and the partial shutdown of a U.S. refinery also added to worries about tight supply.
Saudi officials expressed willingness to defend prices via an OPEC+ production cut, should Tehran secure a nuclear deal with world powers.
BP said on Wednesday it has shut some of its units affected by an electric fire at its 430,000 barrel-per-day Whiting refinery in Indiana. The plant is a key supplier of fuels to the central U.S. and the city of Chicago.
Discussions on an agreement on Iran's nuclear program remain stalled, calling into question any resumption of its exports.
Israel's prime minister said the West is letting Iran manipulate talks over an emerging "bad deal" to curb Tehran's nuclear capabilities.
Signs of falling U.S. crude and product stockpiles also added to the upward pressure on prices.
