Oil prices hit a more than seven-year high on Friday and posted their sixth straight weekly gain as geopolitical unrest heightened concerns about limited energy supplies.

On a weekly basis, benchmark contracts posted their longest streak of gains since October.

Brent crude futures rose 69 cents to settle at $90.03 a barrel, after hitting $91.70, the highest level since October 2014.

U.S. crude closed 21 cents higher at $86.82 a barrel, after hitting a seven-year high of $88.84 during the session.

Tight oil supply pushed the six-month Brent market structure to a steep decline of $6.92 a barrel, the biggest since 2013. expensive than those of the following months, encouraging traders to release oil. storage to sell it quickly.

Major producers in the Organization of the Petroleum Exporting Countries (OPEC) and their Russia-led allies, collectively known as OPEC+, have struggled to raise production levels. The market also reacted to the attacks on the United Arab Emirates by the Houthi group from Yemen.

Prices were supported by concerns over a possible military conflict in Ukraine which could disrupt energy markets, particularly natural gas supplies to Europe.

“So far there has been no supply disruption in Eastern Europe, so I guess the risk premium from these strains is not that high,” said Giovanni Staunovo, analyst at UBS. He added: “Some investors still prefer to hold their exposure.”

US crude futures briefly turned negative earlier in the session.

Matt Smith, director of commodities research at ClipperData, said the relatively softer US rhetoric on Russia may have led to “some of the air blowing out of the tires on this raw rally “.

“But the bigger picture is that with all the geopolitical uncertainty and supply-side concerns, prices continue to get carried away,” he said.

At its Feb. 2 meeting, OPEC+ is expected to stick to a planned increase in its March oil production target, multiple OPEC+ sources told Reuters.