From the Sentinel, a Chicago Jewish newspaper, May 5, 1977:
He added slightly more in this account from the B'nai Brith Messenger the week after:
The full quote in Wikiquote includes, "Jordan, which is a sovereign state with defined borders, cannot raise claims to Haifa and Jaffa, while as a Palestinian, I can undoubtedly demand Haifa, Jaffa, Beer-Sheva and Jerusalem."
Here is a scan of the original article: (h/t iTi)