US President Donald Trump has formally approved a landmark agreement with Saudi Arabia that will provide the country with a civilian nuclear programme, The Wall Street Journal reported.

Citing US officials, the Journal said the deal, which would last 30 years, is estimated to be worth tens of billions of dollars.

According to the report, it is designed to give American companies a central role in developing Saudi Arabia’s nuclear infrastructure while shutting out other foreign competitors.

One of the key components of the new deal would involve American firms building a uranium enrichment plant in Saudi Arabia if a joint review by Washington and Riyadh concludes that the move is justified.

The report said the deal would provide the US with a role in monitoring Saudi Arabia’s nuclear ambitions, which Trump administration officials say could help prevent the programme from being used for weapons development.

However, the agreement, which is expected to be sent to Congress for review in the coming days, is likely to face opposition from lawmakers concerned about expanding nuclear capabilities in the Middle East.