MOSCOW -- Rosneft signed Wednesday an agreement with ExxonMobil (IW 500/1) giving the U.S. super-major access to seven Arctic fields in exchange for the Russian firm's possible participation in a lucrative Alaskan gas project.

The deal -- signed by Rosneft CEO Igor Sechin and ExxonMobil Exploration head Stephen Greenlee in the presence of President Vladimir Putin -- extends a strategic alliance the two companies forged in 2011 focusing on Russia's Arctic field development.

"The agreements signed today bring the already unprecedented scale of the Rosneft and ExxonMobil partnership up to a completely new level," Sechin said.

The two companies said in a statement that ExxonMobil would receive rights to seven of the 12 Arctic fields Rosneft secured from the Russian government earlier this month.

Those terms more than triple the size of ExxonMobil's Arctic involvement to 10 license blocks and push the U.S. firm still further ahead in the global race for the energy wealth believed to be buried in Arctic soils.

Deal Follows Collapse of BP Talks

ExxonMobil struck its deal during an international scramble that followed the unexpected collapse of a similar agreement Rosneft had initially been expected to sign with the U.S. firm's British rival BP (IW 1000/4).

Rosneft has since signed identically structured exploration deals with ENI of Italy and Norway's Statoil.

The international companies receive minority stakes in the Russian-run projects and are responsible for covering the initial exploration and development costs.

But Wednesday's agreement confirms ExxonMobil's status as Russia's most important energy partner by far.