GUATEMALA CITY (AP) — The head of a United Nations-backed anti-corruption commission in Guatemala says power structures that co-opt the government and refuse to give up their privileges are responsible for trying to block the body's work.

In a letter to the U.N. secretary-general, Ivan Velasquez says the intensity of the character attacks and threats on the commission has increased since cases were brought against high-powered political and economic interests.

Guatemala President Jimmy Morales announced last Monday that he was ending the commission's run in the country, but Guatemala's top court blocked the expulsion.

The commission has targeted Morales and his family members in investigations of suspected corruption and campaign finance violations.

Morales says the commission has exceeded its authority. It has been working in Guatemala for 11 years.