Brent ended down 1.23% at $55.41 and WTI ended down 1.62% at $52.27.

Oil prices fell on Friday as investors expressed concern about even weak signals of a return of COVID-19 in China, while U.S. crude inventories rose.

A barrel of Brent North Sea oil for March delivery fell 1.23% or 69 cents to $55.41.

The US barrel of WTI for the same month lost 1.62% or 86 cents to 52.27 dollars.

"The number of COVID-19 cases in China is the top demand concern for investors," said Axi analyst Stephen Innes.

Small foci have emerged in the north of the country in recent weeks. Beijing has registered 19 COVID-19 patients in the past seven days, some of whom are linked to the more contagious English variant of the coronavirus.

“And the announcement of new mobility restrictions for Lunar New Year travel weighs heavily on markets in terms of impact on consumption” of crude, continued Mr. Innes.

The municipality of Beijing, the heart of political power, is indeed extremely cautious as the Lunar New Year holidays (February 11-17) approach.

These usually cause massive influxes in the transport of hundreds of millions of people returning home to spend this holiday, the most important of the year in China, with their families.

Outside of China, “the continued high number of new COVID-19 cases, slow progress on vaccinations in some countries and tougher and longer mobility restrictions in Europe are weighing on investor sentiment,” expanded Eugen Weinberg, of Commerzbank.

The oil market also received a mixed response to the unexpected rise in US oil inventories, the first in five weeks, according to the weekly report from the US Energy Information Agency (EIA).

Commercial crude reserves swelled by 4.4 million barrels (MB) the week ended January 15, 2021, compared to the previous week. The median analyst forecast was for a decline of 1.675 MB. A positive sign, however: demand is up very slightly for the second week in a row.