The young prince, a key ally of President Donald Trump and son-in-law Jared Kushner , has devised a number of explanations to explain his mother's mysterious absence for more than two years, including that she's out of the country's for medical treatment.

Saudi Arabia's Mohammed bin Salman has hidden his mother from seeing his father, King Salman, as the crown prince has worked to consolidate his power, sources told NBC News.

The White House announced this week that the president will meet with the crown prince on Tuesday. It said Trump "looks forward to discussing ways to strengthen ties between the United States and Saudi Arabia and to advance our common security and economic priorities."

U.S. officials, though, told NBC they believe that Prince Mohammed moved against his mother to keep her away from the royal family, worried that she would oppose his plans to seize power and sway the king into preventing it.

The 31-year-old prince, known as MBS, drew the spotlight last June after displacing his cousin to become the crown prince of the oil-rich kingdom. Since then, MBS has arrested hundreds of rival businessmen and family members with an ostensible goal of reducing corruption.

Saudi Arabia's Prince Alwaleed Bin Talal, a prominent member of the country's royal family and one of the country's wealthiest investors, was swept up in the widespread anti-corruption campaign in November.