GENEVA (Reuters) - U.N. human rights chief Michelle Bachelet will make a official visit to Venezuela from June 19-21 and hold separate talks with President Nicolas Maduro and his arch-foe National Assembly chief Juan Guaido, a statement said.

Guaido is the opposition leader who has proclaimed himself interim president in a crisis that has deepened since the United States imposed sanctions in an effort to oust the leftist Maduro. Venezuela's economic meltdown has caused widespread shortages and the flight of more than four million refugees.

In a report to the U.N. Human Rights Council in March, Bachelet said Venezuelan security forces, backed by pro-government militias, had quashed peaceful protests with excessive use of force, killings and torture. [nL8N2174UK]

(Reporting by Stephanie Nebehay; Editing by Mark Heinrich)