President Donald Trump has ordered that all U.S. flags be lowered for the next week to mourn the passing of country singer Dolly Parton, who died on Tuesday.

“Very sad to report that Dolly Parton, one of the greatest country singers, and far beyond, EVER, has just passed away,” Mr Trump wrote on Truth Social. “This is a true loss for millions of people. There has never been anyone like her, and never will.”

“In her honour, I am lowering the American flag throughout the United States for a one week period beginning tonight at 6:00 p.m.,” Mr Trump added. “Rest in Peace, Dolly! The World loves you.”

Ms Parton, who has won 11 Grammy awards, died at 80 in Nashville, her nephew Bryan Seaver announced in an Instagram post on Tuesday.

Mr Seaver did not disclose the cause of death but said she will be dearly missed.

“I have imagined the heaviness of this moment but haven’t truly felt it until now,” Ms Parton’s nephew said.

“It is an honour, an honour that is mixed with absolute pride and great sadness,” Mr Seaver added.

Ms Parton, who was from Tennessee, was famous for her sonorous voice and relatable hit songs like “Jolene,” “Coat of Many Colours,” “9 to 5” and “I Will Always Love You,” which gained new life after Whitney Houston sang it in the 1992 movie “The Bodyguard.” Houston’s version later became the bestselling song of all time by a female artist.

The country singer said she wrote over 3,000 songs, of which 1,000 were recorded and released on more than 50 studio albums; 27 of the albums reached gold and platinum levels, with worldwide sales exceeding 100 million.