Saudi Arabia's King Abdullah is suffering from pneumonia and temporarily needed help to breath through a tube, it has emerged.

The 90-year-old had been transferred to a military hospital in the capital Riyadh earlier this week after experiencing shortness of breath and back pain.

At one point he needed help to breath through a tube - but the procedure was successful and his condition is stable.

Saudi Arabia's King Abdullah (pictured in June) is suffering from pneumonia and temporarily needed help to breath through a tube, it has emerged

The Saudi Royal Court said in a statement: 'It became apparent that there was a lung infection that required the insertion of a tube to aid with breathing on a temporary basis this evening.'

The procedure had resulted in 'stability and success,' it added.

After spending a little more than week at his royal encampment in Rawdat Khuraim, a green oasis about 62 miles (100 kilometers) north of Riyadh, the king returned to the capital on Wednesday and was admitted initially to a National Guard hospital for medical tests.

A Saudi source familiar with the affairs of the royal family said the king would most likely stay in hospital for another week.

The health of the monarch is of extreme importance in the kingdom, where Abdullah holds absolute powers to enact laws and appoint ministers.

His condition is also watched internationally largely due to the country's role as one of the world's largest oil exporters, as well as regionally where the kingdom has used its influence to counter the Islamist Muslim Brotherhood group and Shiite Iran.

The 90-year-old (pictured) had been transferred to a military hospital in the capital Riyadh earlier this week after experiencing shortness of breath and back pain

Abdullah officially assumed the throne in 2005, but has largely been seen as the de facto ruler of Saudi Arabia since the mid-1990s.

He reportedly underwent back surgeries in 2010 in New York City, and in October 2011 and November 2012 in Saudi Arabia.

The aging monarch met 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.

His successor is 79-year-old half-brother Crown Prince Salman. Abdullah has outlived two other half-brothers who held the crown prince post.

In an effort to ease concerns about continuity and stability in the kingdom, 69-year-old Prince Muqrin was appointed deputy crown prince and second-in-line to the throne last year.