"Until the Iranian regime is willing to be a partner for peace, all nations of conscience must work together to isolate it... and pray for the day when the Iranian people have the just and righteous government they so richly deserve" Mr Trump said.
Saudi energy minister Khalid al-Falih stated during the opening of the event that it signalled a "new partnership for the 21 century between Saudi Arabia and the USA".
Trump, accused of using anti-Muslim rhetoric on the election campaign trail, is later expected to tell Muslim leaders of his "hopes for a peaceful vision of Islam".
According to copies of the speech acquired by AP, Trump will say: "This is not a battle between different faiths, different sects or different civilisations".
A month after Donald Trump called for a "total and complete shutdown" of Muslims entering the United States, a hijab-wearing American named Rose Hamid stood up in the grandstands a few rows behind the presidential candidate. The Saudis may put as much as US$45 billion into the venture, people aware of the matter said in January.
White House spokesman Sean Spicer said on Twitter that the defense agreement was the "largest single arms deal in U.S. history" and said other deals amounted to $250 billion in commercial investment.
The drive into the centre of Riyadh in the lead up to 20 May was noticeably different to normal.
To the Muslim leaders, Trump said the United States will seek "gradual reforms - not sudden intervention" in areas like human rights.
The major speech, which Trump delivered Sunday during an Arab-Islamic-American summit in Riyadh to leaders of 55 Muslim-majority countries, marks Trump's first effort to reach out to the world's 1.6 billion Muslims worldwide.
Trump to condemn 'Islamist extremism' in Arab capital The speech drew polite applause for about 20 seconds but there was no standing ovation except from the US official delegation. He praised Egyptian President Abdel Fattah al-Sisi, telling him, "You have done a tremendous job under trying circumstances".
On the second day of his first trip overseas, Trump sought to demonstrate that he'd made progress with an agreement with Gulf Arab states on countering terrorist funding.
The GCC comprises Saudi Arabia, Qatar, Kuwait, Oman, the United Arab Emirates and Bahrain. The phrase is problematic, with critics arguing it portrays atrocities as an expression of Islam when most Muslims would regard such acts as a perversion of their faith.
Trump's speech also comes as he and his administration have continued to defend the executive order barring visitors to the USA from six Muslim-majority countries, which the administration is seeking to reinstate in litigation after it was blocked by federal judges.
The White House did not immediately release a text of the agreement.
Minutes before the summit started in the King Abdulaziz Convention Centre, US Secretary of State Rex Tillerson and Saudi Prince Mohammed bin Nayef signed a memorandum of understanding to create a counter-terrorism centre, which is set to be based in Riyadh.
A senior Israeli Cabinet minister has voiced concern about the U.S.'s $110 billion arms deal with Saudi Arabia.
President Trump's daughter Ivanka Trump spoke to a group of women leaders in Saudi Arabia on Sunday, insisting that more needs to be done to improve the Islamic country's treatment of women. The US president's decision to make Riyadh his first official port of call has been well received with the kingdom's decision makers.
However, Trump's speech is likely to be met with wariness by many in the region, with the president's history of incendiary claims about Islam.
The Oregon Department of Energy , which is responsible for radiological safety, activated its emergency operations center as well. The Hanford site posted on Twitter a video showing workers "beginning prep work... to stabilize and fill a 20x20 ft opening".
Kingston Frazier was shot at least once and the vehicle abandoned in a muddy ditch around 20 kilometres north of the capital. Authorities found Frazier shot at least once in the back seat of his mother's stolen vehicle , which Jackson Police Cmdr.
The developer partnered with NVIDIA to showcase the game on PC at the event, with configurations powered by GTX 1080Ti cards. Hunters in " Destiny 2 " are getting the Arcstrider subclass, which replaces the original Bladedancer in the first game.
Secretary of State Rex Tillerson said economic and diplomatic pressure would continue to be applied to North Korea. Analysts said the Hwasong travelled further than any previous ballistic missile launched by the North.
In what will likely be a back three of Nathan Ake, Kurt Zouma and John Terry , there could be plenty of goals for Sunderland. After a storied Chelsea career, John Terry delivers a heart-felt goodbye to those in attendance at Stamford Bridge.
Re-live Chelsea's stunning season by scrolling through the gallery above of the club's record-breaking 30 wins. Assessing his options for Sunday, Conte said: "John is a champion and he deserves the best.
A spokesperson for NHS Digital said: "At this stage we do not have any evidence that patient data has been accessed". No fewer than 150 countries have so far been hit in the biggest cyber-attack the world has ever witnessed.
The dialogue was robust and collaborative, according to a US senior administration official speaking to reporters at a briefing. Experts say a bomb in the cabin would be easier to make and require less explosive force than one in the hold.
The Saudis deeply distrusted Obama's overtures to Iran and were frustrated by his restrained approach to the Syrian civil war . At the royal al-Yamama palace, the king draped around Trump's neck the king Abdulaziz medal, the country's top civilian honor.
N. Korea fires missile in latest test, US and S. Korea say
Haley noted that this weekend's missile came within 60 miles of Russia's border and said Russian Federation is "all wrong". The missile launches and the threat of a new nuclear test have ratcheted-up tensions with the United States government.
What making the Champions League means for Liverpool
If teams finish level on points, goal difference, and goals scored, teams must play-off to decide who finishes ahead of whom. Fernando Llorente scored a late victor as Swansea came from behind to beat West Brom 2-1 at the Liberty Stadium .
Trump basks in lavish Saudi welcome, escaping troubles in D.C.
Trump was joined on the trip by the CEOs of several major US companies, which announced their own agreements with the Saudis. Ivanka's presence dominated Arabic Twitter traffic, with the phrase "bint Trump" - Arabic for daughter of Trump - trending.
The Greatest Show on Earth says good bye
The company ran two touring circuses this season, one of which ended its run earlier this month in Providence, Rhode Island . The circus' final performance will be in Uniondale, New York on Sunday, but you can watch it LIVE on Facebook and YouTube.
Airline laptop, electronics ban could be extended to Europe
Secretary of Homeland Security John Kelly and "a number of" European ministers was set for the meeting later on Friday". The US is reportedly considering expanding its airline laptop and tablet ban to include the United Kingdom and Europe.
North Korea missile launch tests Trump's China outreach
The missile flew 787 kilometres on a trajectory reaching an altitude of 2,111.5 kilometres, the North's KCNA news agency said. North Korea is banned from developing nuclear and missile technology under United Nations sanctions.
Can Pune be Mumbai's big brother tonight?
Dhoni has been quietly racking up the runs in this edition, focussing on returns-280 runs in 15 matches @ an average of 114. Pune does not have a very deep batting line-up though Daniel Christian and Adam Zampa can blow some biggies if in the arc.
Chibok girls to reunite with parents 'next week'
He also said the others who are at large could recruit new Boko Haram members or launch suicide bombings and other acts of terror. Governor Sani Bello remained hopeful that government would soon facilitate the return of all others still in captivity.
Man City confirm Pablo Zabaleta departure
However, while all focus will be on securing the all-important victory, there's an intriguing sub-plot to keep an eye on. First, it was the FA Cup and then this Premier League that helped us to achieve all we had achieved later".