VATICAN CITY, June 29 (Reuters) - Pope Francis granted top adviser Cardinal George Pell leave to return to his native Australia to face charges of sexual abuse, a Vatican spokesman said on Thursday as Pell declared his innocence.

At a news conference called hours after Australian police charged him with multiple historical sex crimes, Pell said he would return to clear his name after a two-year investigation he described as characterised by "relentless character assassination".

"These charges strengthen my resolve and the court proceedings now offer me the opportunity to clear my name and then return here back to Rome to work," Pell said. (Reporting by Philip Pullella; Editing by Silvia Aloisi and Mark Bendeich)