Incoming chief executive Bernard Looney will not take up either of BP's seats on the board of Rosneft when he takes over in February because of the complexity of the relationship with the Russian oil giant, company sources have said. 

Under an arrangement between Bernard Looney and outgoing CEO Bob Dudley, Dudley will keep one of the seats when he retires in March, the sources said. 

Guillermo Quintero, a Venezuelan national who is also a former BP executive and has ties to the South American country's national oil company PDVSA, will keep the other seat, they said. 

The sources said Rosneft had been informed of the arrangement but did not say how long it was expected to last. 

BP owns nearly a fifth of Rosneft, its biggest foreign investment and the source of a third of its total output.

But Irish man Bernard Looney has not worked in Russia and cannot rival 64-year-old Dudley's long experience of working in and with the country and his deep ties with Rosneft, the Kremlin and Russian President Vladimir Putin. 

"Dudley will stay on the board of Rosneft because the relationship between BP and Moscow is very complicated," a senior BP official told Reuters. 

Looney's decision not to take either of the board seats has not been previously reported. 

Dudley said in October he would stay on the Rosneft board after retiring in March, but did not explain why.

Outgoing BP CEO Bob Dudley

"With his unrivalled experience of both the international oil industry and Russia, Bob will continue to provide valuable experience on the Rosneft Board," BP said in a statement to Reuters. 

Quintero's ties to Venezuela are also important for Rosneft, as the Russian company became an important buyer of oil from the country after it was hit by sanctions by Washington. 

Dudley is chairman of Rosneft's strategic planning committee which focuses on long-term development and sustainability issues, according to Rosneft's 2018 annual report. 

He and Quintero regularly take part in Rosneft board discussions and vote on topics ranging from long-term strategy to dividend payments to shareholders, including BP. 

It is unclear whether either will receive remuneration from BP for sitting on the Rosneft board. 

Neither Dudley nor Quintero hold shares in Rosneft and neither received remuneration from Rosneft last year, according to the 2018 annual report.

Bernard Looney is taking the helm at BP at a time when oil companies are under pressure from investors to meet the goals of the Paris Climate Agreement and reduce carbon emissions from operations. 

The arrangement with Dudley will keep Looney at arm's length from Rosneft and Russia. 

A Rosneft source said this could be beneficial for Looney as the US and the European Union have imposed economic sanctions on Russia and Rosneft over Russia's annexation of Crimea from Ukraine in 2014.

"From a sanctions point of view, the fact that BP's new CEO will not be a board member is even good, allowing him to distance himself a bit (from Rosneft)," a senior source close to Rosneft said. 

"Dudley is trusted by BP, he is an insider. He is friends with Rosneft CEO Igor Sechin, too, which is good for Rosneft." 

Dudley first worked in Russia in 1994 and was later CEO of TNK-BP, a joint venture with a group backed by four Russian oligarchs that turned sour - forcing Dudley at one time to flee Russia - but was eventually sold to Rosneft in 2011, giving BP a 19.75% stake in the oil giant and two board seats. 

He was pivotal in navigating BP's Russian operations through the fallout from Crimea and his lobbying for Rosneft has helped serve BP's interests.