Watch: President Trump arrives in Saudi Arabia

US President Donald Trump has landed in Saudi Arabia, for the first major diplomatic trip of his second term.

The president is hoping to secure significant new investment in the US in the four-day trip to Saudi Arabia, Qatar and UAE.

Saudi Arabia was also the first country that Trump visited during his first term of office, going against the modern practise of US presidents to start with the UK, Canada or Mexico.

Securing new investments in the US from Gulf states, and particularly from their state-backed sovereign wealth funds, will help Trump to signal back home that his "America First" agenda is delivering results.