Foxnews-- Seats for an Iranian delegation sat empty on Monday at the conference being held in Abu Dhabi, the capital of the UAE. Conference staff said the Iranians had cancelled their appointment to speak at the event.

Iranian authorities could not be immediately reached for comment.

Yukiya Amano, the head of the International Atomic Energy Agency, avoided speaking about Iran in his address at the conference.

Amano visited Tehran on Sunday.

The UAE and neighboring Saudi Arabia remain highly suspicious of Iran and skeptical of the nuclear deal it struck in 2015 with world powers.

Donald Trump has declined to re-certify the deal, sending it to Congress to address.