LOS ANGELES: US singer Scott McKenzie, who sang “San Francisco (Be Sure to Wear Flowers in Your Hair),” the unofficial anthem of the counterculture movement of the 1960s, has died here at the age of 73, his website reported Monday.

“It is with much sadness that we report the passing of Scott McKenzie in LA on the 18th of August, 2012,” said a statement posted on the site.

“Scott had been very ill recently and passed away in his home after two weeks in hospital,” it added.

According to the site, McKenzie was in and out of hospital since 2010 after falling ill with Guillain-Barre Syndrome, a disease affecting the nervous system.

It is thought he may have had a heart attack in early August, the site added.

“San Francisco” was written by John Phillips, the leader of the 1960s group The Mamas and the Papas, but it was sung by McKenzie.

In 1988, McKenzie also co-wrote with Phillips, Mike Love and Terry Melcher the Beach Boys hit “Kokomo.” Scott spent much of the 1990s touring with the Mamas and Papas.

Eventually, with no original members left, the group disbanded.