(Bloomberg) -- Russian weekly oil refining is near an 11-month low as flooding hampers operations and repairs to plants affected by drone attacks slow down.

Russia processed 5.22 million barrels of crude a day April 11-17, according to a person with knowledge of industry data. That’s about 10,000 barrels a day, or 0.2%, below the average of the prior seven days, Bloomberg calculations show. 

With the invasion of Ukraine well into its third year, Kyiv has been using drones to hit Russia’s most important industry. The Ukrainian government has defended that strategy in the face of US concerns, saying it’s seeking to curb fuel supplies to the front line and cut the flow of petrodollars to Kremlin coffers. 

Read More: US Slams Strikes on Russia Oil Refineries as Risk to Oil Markets

Earlier this year, drones targeted key Russian refineries, causing their partial or complete shutdown. There’s been no further damage during the past month, giving operators time to conduct repairs, yet the pace of recovery has slowed. 

In the April 11-17 period, most of the major facilities affected ran at levels near the previous weekly average — and still below pre-attack output. 

Daily crude processing rates at refineries damaged by Ukrainian drone attacks averaged 1.23 million barrels April 1-17, according to the person. That’s some 280,000 barrels a day lower than the average for January 1-24, before the attacks, Bloomberg calculations show.

Rosneft PJSC’s Tuapse plant hit at the end of January remains offline, and other damaged refineries owned by the producer still haven’t recovered their runs to pre-attack levels. Crude processing at Lukoil PJSC’s Norsi facility in Nizhny Novgorod is also below January levels, but the facility also had a technical incident earlier this year that also put pressure on its operations

During April as a whole, Russian refinery runs have averaged about 5.23 million barrels a day, near the lowest levels since last May.

Flooding Impact

Severe weather has also affected processing, with floods in Russia’s Urals region forcing the Orsk refinery offline April 7. In the latest reporting period, the facility didn’t process any crude, according to the person familiar with the matter.

Read More: Russia, Kazakhstan Suffer Worst Floods in 80 Years as Snow Melts

In the previous seven days, the facility had churned through an average 26,500 barrels a day. The loss of those volumes became one of the biggest contributors to the overall decline in Russian processing rates April 11-17, the person said. Orsk is preparing to restart operations, the facility’s press service said Friday.

Two other refineries — the independent Novoshakhtinsk plant and Lukoil’s Perm site — lowered average processing by a combined 45,000 barrels a day. That may be due to maintenance, which Russian operators typically carry out in spring before demand rises in summer.

Press offices at the Novoshakhtinsk refinery and Lukoil didn’t immediately respond to requests for comment.

(Updates with total crude processing rates at damaged refineries in sixth and seventh paragraphs.)

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