Per Wastberg, a member of the Swedish Academy that awarded the 2016 Nobel Prize in literature to Bob Dylan says Dylan’s silence after receiving the award is “impolite and arrogant.”

The singer-songwriter has not responded to numerous phone calls from the Swedish Nobel Academy, or commented in any other way on the prize.

On Oct. 13, the day the literature prize winner was announced, Dylan played in Las Vegas and made no comment at the concert.

The 75-year-old artist was credited with creating “new poetic expressions within the great American song tradition.”

“We have agreed not to lift a finger. The ball lies entirely on his half,” Wastberg said in a recent interview. “You can speculate as much as you want but we don’t.”

It is not clear if Dylan will accept the prize yet. Only two people have declined a Nobel Prize in literature: Boris Pasternak, under pressure from Soviet authorities in 1958, and Jean-Paul Sartre, who declined the honor in 1964.