* Indian companies buy 29.9 pct of Taas-Yuriakh oil field
* Raise stake in Vankor field to 49.9 pct
* Rosneft aims to finalise Indian refinery deal by end-June (Recasts, adds detail)
NEW DELHI/MOSCOW, March 16 (Reuters) - Indian statecompanies signed energy deals worth billions of dollars withRussia's Rosneft on Wednesday to buy into its mostpromising assets in Siberia, stepping up a drive to cut NewDelhi's dependence on imports.
Prime Minister Narendra Modi, who wants to cut India's oilimports by 10 percent in six years, is steering efforts to buyforeign energy assets, taking advantage of low global oil pricesand a slowdown in China's overseas acquisitions.
Under the deals signed with Rosneft CEO Igor Sechin, theIndian companies will raise their stake in the Vankor oil fieldto almost 50 percent and buy about 30 percent of theTaas-Yuriakh field.
The deals will help Rosneft, the world's biggested listedoil producer by output, to pay off debts incurred in its $55billion acquisition of TNK-BP in 2013.
Russia is keen to develop and deepen its Soviet-era economicties with India and sell oil to one of the world'sfastest-growing economies at a time when its own economy isstagnant, hit by Western sanctions and a plunge in global oilprices.
Modi had pitched to Russian President Vladimir Putin for thegranting of stakes to Indian oil firms during his visit toMoscow in December.
The deals will help India to secure Russian oil output,while Rosneft will gain access to the Indian market, Sechin toldreporters in New Delhi.
Sechin met Essar Oil officials during his visitand said that Rosneft hopes to conclude a deal to buy a 49percent stake in the 400,000 barrel-per-day Vadinar refinery inwestern India by the end of June.
The proposed deal would give Rosneft an additional outletfor its oil as it grapples with a global crude supply glut.
ENERGY BRIDGE
"We are establishing a reliable energy bridge between ourcountries, which will be developing the interests of both Russiaand India," Sechin said.
A consortium of Oil India, Indian Oil Corp and Bharat PetroResources (BPRL), a unit of BharatPetroleum Corp, has bought 29.9 percent stake inRosneft's Taas-Yuriakh field.
The companies will together pay $1.121 billion for theirshare in the operation and $180 million each for future capitalexpenditure, a source with knowledge of the deal said.
Meanwhile, India's Oil and Natural Gas Corp signedan initial deal to raise its stake in the Vankor project to 26percent from 15 percent, while the other three companies couldtogether pick up 23.9 percent.
A final deal for Vankor will be signed in June, sources toldReuters last week.
If the deals go through, Rosneft will retain 50.1 percent ofVankor, which produced 22 million tonnes of oil in 2014,representing about a tenth of the company's total output.
Vankor's oil is shipped to Asia, mostly to China.
Indian companies could pay close to $3 billion for boostingtheir Vankor stake, based on the price ONGC paid for its 15percent stake in the project, an ONGC source told Reuters.
IOC-Oil India-BPRL also signed a preliminary deal to buy astake in Rosneft's Vankor cluster - a separate group of smalloil fields.
(Reporting by Nidhi Verma and Neha Dasgupta in New Delhi,;Alexander Winning and Katya Golubkova in Moscow; Editing byDavid Goodman)