Saudi Arabia -- Saudi Arabia's 90-year-old King Abdullah was admitted to a hospital on Wednesday for medical tests, the official Saudi Press Agency reported.
The king, whose age and frequent hospitalisation have raised concerns about the future leadership of the key oil producing country, was admitted to the King Abdulaziz Medical City in Riyadh, a court statement carried by the official SPA news agency said on Wednesday.
Just last week, the king had left the capital city to spend time at the royal encampment in Rawdat Khuraim, a green oasis about 62 miles (100 kilometers) north of Riyadh.
It was at that resort where the aging monarch met US President Barack Obama in March and appeared before the press wearing an oxygen tube. Official photographs of the king have also shown him in a wheelchair.
Abdullah's half brother Salman, 77, is next in line to the throne. He was named crown prince in June 2012 following the death of Prince Nayef bin Abdul Aziz.
The king's absence from the public gaze for some time last year prompted rumours on social media networks that his health was deteriorating.
He underwent two operations in October 2011 and November 2012 to correct "ligament slackening" in the upper back.
Saudi Arabia is an absolute monarchy with no elected parliament. The king has sole power to ratify legislation and appoint ministers.