By Pedro Fonseca

RIO DE JANEIRO (Reuters) - Former Brazil striker Ronaldo will announce his retirement from soccer on Monday, he told a Brazilian newspaper on Sunday.

The 34-year-old three-times world player of the year has a contract with Corinthians until the end of 2011 but is bringing his retirement forward after the team's shock early elimination from the Libertadores Cup and violent protests from fans.

Ronaldo told the Estado de Sao Paulo newspaper's website (www.estadao.com.br) his regular injury problems were one of his main reasons for quitting now.

"I can't take it any more," Ronaldo said. "I wanted to carry on, but I can't. I plan a move (in a game) but I cannot execute as I wish. The time is up. But it was nice, dammit."

Ronaldo, who will make his announcement in a news conference at the Corinthians training ground on Monday, is ending a brilliant career in which he scored more than 400 goals including a record 15 at World Cups.

Ronaldo, who left Brazil's Cruzeiro for PSV Eindhoven at the age of 18 and played for both Milan clubs, Barcelona and Real Madrid, helped Corinthians win the Copa Brasil and Paulista (Sao Paulo) state championship last year.

But Corinthians disappointed in the two big competitions of 2010, their centenary year, failing to get past the round of 16 of the Libertadores cup or win the Brazilian championship.

Ronaldo missed many matches through injury and fans began to show their irritation.

(Writing by Rex Gowar in Buenpos Aires; editing by Ed Osmond)