Lenders to Russian aluminum giant United Company Rusal, which is in talks to restructure its multibillion-dollar debt, have requested the company's clarification on how it will be able to finance its part of an ambitious Siberian project and repay its part of the loan associated with it, people familiar with the matter told Dow Jones Newswires Wednesday.

Barclays Bank PLC (BCS), acting as the facility agent, sent a letter to Rusal, in which it asks the company to explain how it will be able to meet its financing obligation in respect to the Boguchansk Energy and Metals Complex, or BEMO. People familiar with the matter said that the letter sent had support of majority of the lenders.

Rusal and state-controlled hydropower monopoly RusHydro (HYDR.RS) are building the 3,000-megawatt plant, which will feed the Boguchansk aluminum smelter, also jointly built by Rusal and RusHydro.

The banks, including Barclays Capital, Calyon, ABN Amro Bank and Russia's Sberbank (SBER.RS), have lent $520 million to the BEMO partners as a bridge loan.

In its letter, Barclays asked Rusal how it will be in a position to repay its 50% share of the loan on the maturity date in early 2010.

The letter also asks Rusal to give its rationale for the continuation of the project, given Rusal's production cuts and its previous statements that the smelter launch had been indefinitely suspended.

Rusal, facing a sharp drop in demand in aluminum, has been seeking to delay the launch of the project, but the Russian government said that it will proceed with construction of the plant as planned.

Rusal representative Vera Kurochkina wasn't able to confirm or deny the existence of the letter late Wednesday, but said that Rusal considers BEMO a strategic project and has no intention to leave it.

She reiterated that Rusal's lenders approved the company's investment in BEMO in December and that the smelter will guarantee a steady demand for electricity from the power station.

In May, Rusal declined its lenders' proposal to cede its stake in BEMO in return for canceling of it part of the bridge loan, deeming the proposal "unacceptable."

The BEMO's bridge loan is separate from Rusal's own $7.4 billion debt to more than 70 international banks, which it's seeking to restructure. The company said Wednesday that the creditors intend to give it an extension of a standstill agreement until July 28 to restructure this debt.

-By Alexander Kolyandr, Dow Jones Newswires; +44 20 7842 9410; alexander.kolyandr@dowjones.com