Saudi Arabia\'s 90-year-old King Abdullah has congratulated Qatar\'s new young emir Sheikh Tamim bin Hamad al-Thani, 33, who took power Tuesday after his father abdicated, state news agency SPA reported. \"We are happy to express to you in the name of the people and Saudi Arabia\'s government and in our name, our sincerest congratulations,\" King Abdullah said in a statement published by SPA. \"We are confident that you will continue the journey of your father ... and his efforts in serving the state of Qatar and its brotherly people as well as strengthening relations between the two nations,\" the king said in his message to Tamim. Sheikh Tamim has played a major role in improving relations between Qatar and regional powerhouse Saudi Arabia, which had been strained until 2007 over a border dispute. Sheikh Hamad, 61, abdicated in favour of his son on Tuesday, the first ruler to voluntarily cede power in the Arab world, where autocratic rulers held power uncontested for decades until the Arab Spring revolutions that toppled regimes in Tunisia, Egypt and Libya. In Saudi, King Abdullah\'s age and frequent hospitalisation have raised concerns about the future leadership of the ultra-conservative Gulf kingdom, a key player in the Middle East and a major exporter of oil. Recently, the king had carried out a series of reshuffles of princes holding government posts in the OPEC kingpin.