July 8 (Reuters) - Representatives of Venezuela"s government and opposition are set to meet in Mexico beginning in August for a new round of negotiations aimed at ending the South American country"s deep political crisis, five people familiar with the matter said. The dialogue would be mediated by international parties and is supported by Norway, which acted as a mediator in a previous negotiation attempt in 2019 and is currently in touch with both sides to set the agenda, the sources said. A Norwegian delegation is visiting Caracas this week, one source said. President Nicolas Maduro, who has overseen an economic collapse in the once-prosperous OPEC nation, has said he is willing to negotiate with opposition leader Juan Guaido, but only over an agenda focused on the lifting of U.S. sanctions. Washington accuses Maduro of rights violations and rigging his 2018 re-election. Maduro denies those charges. Guaido, by contrast, has said his delegation is seeking conditions for free and fair presidential and parliamentary elections. The planned negotiations come two weeks after the chief diplomats for the United States, Canada and the European Union said they would be willing to revise their sanctions on Maduro"s government if negotiations lead to "meaningful progress" toward transparent elections. The return to the negotiating table represents a change in tack for the opposition, which has in the past accused Maduro"s government of using rounds of dialogue to buy time and defuse international pressure. The government withdrew from the 2019 round, held in Barbados, after former U.S. President Donald Trump tightened sanctions aimed at ousting Maduro. President Joe Biden"s administration, which says it is reviewing the sanctions policies it inherited, has not relaxed sanctions on Venezuela"s oil and financial sectors and has maintained support for Guaido, recognized as the South American country"s rightful leader by Washington and dozens of other Western democracies. The delegations for both sides will be larger compared with the Barbados round, the sources said. "It"s a more complete and complex process that has not existed until now," one of the sources said. Norway"s foreign ministry referred to a May 10 statement in which it said it remained in contact "with the political and social actors of Venezuela on a regular basis" and called for a "peaceful, inclusive and lasting solution to the crisis in Venezuela." Neither Mexico"s foreign ministry nor Venezuela"s information ministry immediately responded to requests for comment. Guaido representatives recently completed trips to Washington, Brussels and Madrid to drum up support for the opposition"s proposed "national salvation" plan, which would condition the gradual lifting of sanctions on the advent of free and fair elections and the entry of humanitarian aid. More than two years of international diplomatic pressure and sanctions have not been enough to oust Maduro, who calls Guaido a U.S. puppet seeking to depose him in a coup and retains the support of Russia, China and Cuba, as well as Venezuela"s armed forces.