US President Donald Trump concludes his Gulf tour on Thursday by heading to the UAE, following stops in Saudi Arabia and Qatar, where he concluded deals and secured billions of dollars in pledges.

Although his first official trip of his second term, apart from attending Pope Francis's funeral at the Vatican, was confined to the Gulf, Trump, always ready for surprises, has not ruled out continuing his trip to Turkey if Russian President Vladimir Putin attends upcoming talks with Ukraine.

Trump heads to the UAE capital, Abu Dhabi, after a stop in Qatar, where the US president hailed what he called a "record deal" worth $200 billion to purchase Boeing aircraft.

Trump began his trip in Saudi Arabia, which promised $600 billion in investments, including a US arms deal that the White House described as "the largest in history."