GENEVA, May 14 (Xinhua) -- Peru captain Paolo Guerrero will miss this summer's World Cup in Russia after the Court of Arbitration for Sport (CAS) extended his doping ban by eight months on Monday.

Guerrero was given a 12-month ban last December after testing positive for cocaine metabolite benzoylecgonine following Peru's World Cup qualifier against Argentina in Buenos Aires on October 5.

The penalty, backdated to November, was halved by FIFA's appeal committee less than two weeks later.

The case was referred to the CAS after a challenge by the World Anti-Doping Agency. The Flamengo striker also appealed in a bid to clear his name.

A CAS panel said it accepted the 34-year-old's claim that he did not attempt to enhance his performance by taking a prohibited substance.

"However, the panel considered that the player did bear some fault or negligence, even if it was not significant, and that he could have taken some measures to prevent him from committing the anti-doping rule violation," CAS said in a statement.

The ruling means Guerrero will be banned from all football-related activities until next January.

Peru qualified for the World Cup, to be played from June 14 to July 15, for the first time in 36 years by beating New Zealand in an inter-continental playoff last November.

Guerrero, who returned for Flamengo in their 2-0 victory over Internacional in Brazil's Serie A on May 6, published an emotional video on social media in which he reiterated his innocence.

"To be going through this injustice after six months and today to have a decision where the CAS ratifies fourteen months of suspension for me is very hard. It's very hard for me and my family to take," the former Bayern Munich player said.

"I have not used any type of drug or prohibited substance. I never have because I am a professional footballer and I have never needed to try that kind of thing. I know what things an athlete can consume and cannot consume."