RIO DE JANEIRO, Feb. 21 (Xinhua) -- A deal that would see highly rated Gremio midfielder Arthur move to Barcelona next January is "90% complete", according to reports in Brazilian media.

Officials from both clubs have been in talks since December over the 21-year-old, who has been likened to Barcelona great Xavi Hernandez.

"You could say that it's 90% complete. There are just some little details remaining," Globoesporte quoted a Barcelona official as saying.

It added that all parties had agreed in principal to a five-year contract, meaning Arthur would be tied to the Catalan club until early 2024.

Earlier, Gremio president Romildo Bolzan denied that a deal had already been struck.

"There have been plenty of discussions, but at this stage the transfer cannot be considered a foregone conclusion." He told Radio Bandeirantes.

Arthur has also been linked to Real Madrid, Manchester City, Chelsea and Monaco after a superb 2017 season in which he helped Gremio win the Copa Libertadores, South America's top club competition.

In October, the Brazilian club extended his contract until 2021 and added a 50 million-euro buyout clause.

The former Goias youth-team player earned his first call-up to Brazil's national squad last October.