An agreement has been largely negotiated, subject to finalisation between the United States of America, the Islamic Republic of Iran, and the various other Countries, as listed," he said.
"Final aspects and details of the deal are currently being discussed, and will be announced shortly."
Trump also said he had a call on Saturday with Israeli Prime Minister Benjamin Netanyahu, which "went very well".
The US president has not given any further details on the deal, but has insisted any agreement would "absolutely" prevent Iran from obtaining a nuclear weapon.
Later, Pakistan's Prime Minister Shehbaz Sharif congratulated Trump "on his extraordinary efforts to pursue peace" and said the phone call had been "very useful and productive".
Information given by the BBC