Pinter, 72, was at the National Theatre in London to read from War, a new collection of his anti-war poetry that had been published in the press in response to events in Iraq.
In conversation on stage with Michael Billington, the Guardian's theatre critic, Pinter said the US government was the most dangerous power that had ever existed.
The American detention centre in Guantanamo Bay, Cuba, where al-Qaida and Taliban suspects were being held, was a concentration camp.
The US population had to accept responsibility for allowing an unelected president to take power and the British were exhausted from protesting and being ignored by Tony Blair, a "deluded idiot" Pinter hoped would resign.
After a big operation for cancer, Pinter returned to public life last year to speak out against American belligerence. He called it a return from a "personal nightmare" to an "infinitely more pervasive public nightmare".
The playwright said: "The US is really beyond reason now. It is beyond our imagining to know what they are going to do next and what they are prepared to do. There is only one comparison: Nazi Germany.
"Nazi Germany wanted total domination of Europe and they nearly did it. The US wants total domination of the world and is about to consolidate that.
"In a policy document, the US has used the term 'full-spectrum domination', that means control of land, sea, air and space, and that is exactly what's intended and what the US wants to fulfil. They are quite blatant about it."
Pinter blamed "millions of totally deluded American people" for not staging a mass revolt.