Spanish construction firm Sacyr Vallehermoso's board of directors has voted to remove chairman Luis del Rivero, who had forged an alliance with Mexico's Pemex to gain more power within Spanish oil major Repsol-YPF.

Sources close to the heavily indebted construction group told Efe that CEO Manuel Manrique, who voted for Del Rivero's removal, will take over as chairman and that the new co-vice chairmen will be Demetrio Carceller, Sacyr's largest shareholder, and Juan Abello.

The board members discussed Sacyr's high indebtedness associated with its move in 2006 to acquire a 20 percent stake in Repsol-YPF, as well as the possible refinancing of the loan used to purchase that stake.

That issue came to the forefront following a media report earlier this month that some foreign banks involved in the transaction are not willing to roll over Sacyr's debt.

Del Rivero's ouster late Thursday could lead to an end to a shareholder pact on Repsol's board between Sacyr and Mexican state-owned energy company Petroleos Mexicanos, which together own 29.5 percent of the Spanish oil firm.

The ousted chairman had been the driving force behind the alliance, which analysts say was aimed at reducing the power of Repsol-YPF Chairman and CEO Antonio Brufau by forcing him to give up one of his two roles.

Del Rivero had been at odds with Brufau's management of Repsol and particularly his decision to give greater priority to oil exploration at the expense of higher dividend payouts to shareholders.

Sacyr also may be forced to sell a 10 percent stake in Repsol valued at approximately 2.6 billion euros (some $3.5 billion) to repay the loan that it took in 2006 to acquire its stake in Spain's largest oil company and which comes due in December.

The company took that stake shortly before the bursting of Spain's property bubble and the subsequent plunge in the company's share price.

Three Spanish savings banks that hold stakes in Sacyr and also are participating in the process of refinancing the $6.8 billion loan have been calling for a share sale.

Del Rivero on Thursday had announced a pact to vote as a block with two other leading shareholders - Jose Manuel Loureda Mantiñan and Javier Gayo Pozo, who along with the now-ousted chairman control 26.95 percent of Sacyr - but it was not enough to prevent his removal.

Mexican state-owned Petroleos Mexicanos, for its part, had no comment on the removal of Del Rivero, telling Efe the decision was an "internal matter."

"We have nothing to say with respect to what's happening at Sacyr," a Pemex spokesperson said, refusing to speculate on the impact of Del Rivero's ouster on the future of the Sacyr-Pemex voting alliance on Repsol's board.

That pact - under which Pemex lifted its interest in Repsol to 9.49 percent, giving the two companies a combined stake of 29.5 percent - sparked criticism in Spain and aroused the suspicions of the political opposition in Mexico.

On Wednesday, Pemex CEO Juan Jose Suarez Coppel defended the company's move to increase its stake in Repsol before the Mexican lower house's finance and energy committees and denied that funds had been channeled away from planned investments in Mexico.

He also said that Pemex has no intention of further expanding its stake in Repsol and stressed the importance of that company remaining Spanish-controlled.