Spanish oil group Repsol tried to sell its 57.4-percent stake in Argentine subsidiary YPF to a Chinese firm shortly before YPF was expropriated, the Financial Times said Wednesday.

Repsol tried secretly to sell its 57 percent in YPF to the Chinese buyer but the attempt was scuppered by Argentina's announcement on Monday that it was nationalising the offshoot, it said.

A person involved in the matter told the paper that the Chinese company was China Petroleum & Chemical Corp (Sinopec).

Repsol was seeking more than $10 billion (7.6 billion euros) for the stake, the paper said, but had not planned to tell the Argentine government until negotiations were complete.

Repsol executive chairman Antonio Brufau told a news conference Tuesday that several international investors had shown interest in the company's stake in YPF.

He estimated the value of the Repsol stake at $10.5 billion. "We have received signs of interest with similar values," he told the news conference.

Brufau said he had tried to speak to Argentina's President Cristina Kirchner about the possible change in shareholder so as to ease tensions but said the head of state "did not have time to receive me".

A Repsol spokesman told AFP that the group had received firm offers from two or three companies but declined to give further details.

Sinopec, China's largest refiner, and Repsol are already partners in Brazil where the Chinese group has a 40-percent stake in the Spanish group's Brazilian subsidiary.