Ecuador's attorney general on Thursday accused Vice President Jorge Glas of unlawful association in the giant corruption case involving Brazilian constructor Odebrecht.

Glas is in pre-trial preventive custody and has not been formally charged, but attorney general Carlos Baca said on Twitter he was seeking an indictment on "charges against the vice president and 12 others in the crime of unlawful association."

The crime carries a penalty of three to five years in prison. The prosecution has previously warned that Glas and other defendants in the case could also be charged with more serious crimes, such as bribery and illicit enrichment.

Glas was taken into custody on October 2, the highest-ranking politician to be connected to the multi-million Odebrecht kickbacks case, which has cast a cloud over politicians in several Latin American countries, including Mexico, Peru, Panama and Venezuela.

He told AFP in an October 14 interview in Quito's Penitentiary 4 prison that he was a victim of the construction giant's revenge after he was instrumental in kicking the company out of Ecuador in 2008 following a dispute over repair of a hydroelectric plant.

Glas, who was minister of strategic sectors before becoming vice president in 2013, has denied any link to the Odebrecht scandal, though his uncle, Ricardo Rivera, has been arrested for his alleged involvement.

Under investigation by the US Justice Department, Odebrecht agreed in December to pay a record $3.5 billion fine after admitting to paying $788 million in bribes across 12 countries to secure contracts.