Mexican President Enrique Pena Nieto has been hit with fresh allegations over the ownership of his personal residence in Mexico City.
The Financial Times newspaper reported that Pena Nieto's mansion was owned by a Mexican member of the Chinese-led group that had won a rail contract in the country last week, before losing the deal.
The sprawling mansion is thought to be worth around $7m (£4.4m), although the allegations state that Pena Nieto did not pay for the residence.
The presidency said in a statement that the first lady, Angelica Rivera, had signed a contract with IIC, a company owned by Juan Armando Hinojosa, to purchase two properties in January 2012. The property would be transferred to her name when she had paid it off, the statement said.
Hinojosa is the head of Grupo Higa, a construction company that owns Constructora Teya, which was part of the Chinese-led consortium that had won the bid for a high-speed rail contract.
The scandal over the presidential mansion and the train contract have added fuel to widespread protests over recent days, where thousands of Mexicans demanded progress in the investigation to find 43 missing students.
The phrase #YaMeCanse (enough, I'm tired) began trending on Twitter, in reference to the corruption and violence that protesters say the government has failed to stop.
The country's attorney-general, Jesus Murillo Karam, had initially used the phrase at a press conference on Friday.
Despite the protests, Pena Nieto has travelled to China for the Apec summit, where he arrived on Monday (10 November).