The US president began his nine-day trip of the Middle East and Europe as he faced growing criticism at home over the sacking of FBI chief James Comey.
Mr.Trump, First Lady Melania and their daughter Ivanka were welcomed by Saudi King Salman bin Abdulaziz, as they stepped off Air Force One.
The king praised Trump and said he hoped his visit would “strengthen our strategic co-operation”, before presenting him with the country’s highest civilian award, The King Abdulaziz Medal.
At a banquet hosted by the king, the president was served his favourite, steak and ketchup, alongside more traditional local dishes.
The White House said the agreement, which includes options worth up to £268billion in the next decade, demonstrates the United States’ commitment to partners in Saudi Arabia and other Gulf countries.
Tens of thousands of new jobs in the US defence industrial base would also be created.
The deal includes a £4.6billion pledge for 150 Lockheed Martin Blackhawk helicopters to be assembled in Saudi Arabia, which will create 450 jobs.
There is also a £5.4billion partnership with General Electric. However, Trump’s trip to Saudi, Israel, Italy, The Vatican and Belgium has failed to quell the storm over his dismissal of FBI director Comey.
Comey To Testify
It was announced yesterday that Mr Comey is to testify in public during the US inquiry into Russian interference in the presidential election.
Trump has denied collusion and denounced the appointment of a special counsel as part of a “witchhunt”.
He is due to deliver a speech in Riyadh today aimed at rallying Muslims in the fight against Islamic extremists.
The decision to make his first official trip abroad to Saudi Arabia and Israel, which both share his antagonism towards Iran, is seen as a criticism of President Obama, who he has accused of “going soft” on Tehran.
Meanwhile Iran has re-elected moderate President Hassan Rouhani, the architect of a fragile relationship with the West, with a huge majority.