DUBAI, United Arab Emirates (AP) — Iran and the United States held a fourth round of negotiations Sunday over Tehran’s rapidly advancing nuclear program, just ahead of a visit by President Donald Trump to the Middle East this week.

Iran is preparing for a visit by Russian President Vladimir Putin, Iran's government spokesperson Fatemeh Mohajerani was quoted by Russia's state RIA news agency as saying on Monday. "Putin's trip to Tehran is currently being worked out,

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On the first leg of his Gulf visit in Riyadh, Trump drew a stark contrast between what he called the "constructive vision" of Saudi Arabia and the "collapse and suffering" he said had been caused by Iranian leaders.

Russian President Vladimir Putin has an invitation to visit Iran, but the dates have not yet been agreed, Kremlin spokesman Dmitry Peskov said on Wednesday.

An Iranian official told CNN that recent indirect talks with the United States aimed at addressing Tehran’s nuclear program and lifting sanctions were “not genuine” from the American side and were likely designed from the outset as a “trap to draw the situation toward tension.

President Trump issued this warning to Iran during a speech in Saudi Arabia on Tuesday. "This is an offer that will not last forever. The time is right now for them to choose," Trump said. "Things are happening at a very fast pace.

Nadergholi Ebrahimi has asked Supreme Leader Khamenei to rethink Iran's nuclear policy if negotiations with the U.S. collapse.

Iran will hold talks in Istanbul on Friday with European parties to their now-moribund 2015 nuclear deal, two European and an Iranian diplomatic source said on Tuesday,