GOA, India (Reuters) - A group led by Russian oil major Rosneft <ROSN.MM> will invest around $12.9 billion in India's Essar Oil <ESRO.CL>, Chief Executive Igor Sechin told reporters on Saturday.

Sechin said a refinery and port owned by the Indian firm were worth around $10 billion and $2.9 billion respectively.

India and Russia signed a deal on Saturday to pave the way for a group led by Rosneft to acquire Essar.

Officials from Russian lender VTB <VTBR.MM>, which is giving Essar $3.9 billion in credit for debt reconstruction, said Rosneft would pay around $3.5 billion for its stake in Essar, the same amount as European trader Trafigura and Russian fund UCP.

(Reporting by Denis Pinchuk; Writing by Jack Stubbs; Editing by Andrew Heavens)