CARACAS, Venezuela (AP) — A four-city U.S. tour by classical music maestro Gustavo Dudamel is being cancelled following President Nicolas Maduro's complaints about the Venezuela-born conductor's criticism of the government's crackdown on protests.

Dudamel's tour with the government-backed Venezuelan National Youth Orchestra was set to begin Sept. 9 near Washington before continuing to Chicago, Los Angeles and San Francisco.

Dudamel on Twitter Monday called the cancellation "heartbreaking" and said he would continue "to fight for a better Venezuela."

Dudamel gave no reason for the cancellation, but Maduro last week blasted the Los Angeles Philharmonic's musical director, accusing him of being duped by Venezuela's enemies into criticizing the government that has for years been one of his biggest promoters.

Dudamel is scheduled to tour China with another government orchestra in October.