Saudi Arabia's Crown Prince Nayef has left the country for a trip that includes medical tests.

The official Saudi Press Agency says the heir to the throne will undergo the tests during what was described as a "personal vacation." The report Saturday gave no other details on Nayef's location.

Nayef, who is in his late 70s, had medical tests in March in Cleveland. The kingdom has given no further information.

Nayef was named crown prince in October following the death of Prince Sultan.

He has served as interior minister for three decades in the oil-rich kingdom. Nayef is considered close to the hard-line Islamic clerical establishment that holds vast power in Saudi, a critical Western ally.