Saudi Arabia's King Abdullah bin Abdulaziz Al Saud has died, according to the state-run Saudi Press Agency.
He has been succeeded by his brother, 79-year-old Prince Salman bin Abdul Aziz.
The Royal Court is in mourning following the 90-year-old's death. "God bless the deceased," the press agency tweeted.
#عاجل_واسالديوان الملكي ينعي الأمة الإسلامية والعربية بوفاة خادم الحرمين الشريفين الملك عبدالله بن عبدالعزيز آل سعود- رحم الله فقيد الأمة— واس (@spagov) January 22, 2015
King Abdullah had been hospitalized for several weeks due to a lung infection, according to the BBC. He died Friday at 1 a.m. local time.
He came to power in 2005 when his brother, King Fahd bin Abdulaziz Al Saud, died from a stroke. While on the throne, Abdullah worked closely with Western countries, including the United States in its fight against al-Qaeda, and sought to modernize Saudi Arabia. During his reign, women's rights were expanded to an extent, including promising the right to vote and run for municipal office, but women in the country still face many limitations. Saudi Arabia remains the only country in the world in which women are not allowed to drive.
In addition, Abdullah and fellow Sunni Arab monarchs staunchly opposed the Middle East's wave of pro-democracy uprisings, seeing them as a threat to stability and their own rule. After the 2011 Arab Spring uprisings in particular, Saudi Arabia clamped down on any dissent.
And while the king maintained the historically close alliance with the U.S., there were frictions as he sought to put those relations on his oil-rich country's terms. He was constantly frustrated by Washington's failure to broker a settlement to the Israel-Palestinian conflict. He also pushed the Obama administration to take a tougher stand against Iran and to more strongly back the mainly Sunni rebels fighting to overthrow Syrian President Bashar Assad.
When al-Qaeda militants in 2003 began a wave of violence in the kingdom aimed at toppling the monarchy, Abdullah cracked down hard. For the next three years, security forces battled militants, finally forcing them to flee to neighboring Yemen. There, they created a new al-Qaeda branch, and Saudi Arabia has played a behind-the-scenes role in fighting it.
Former President H.W. Bush called the king a "wise and reliable ally" in a statement.
Herewith the statement by Former President @GeorgeHWBush (41) on the passing of King Abdullah of Saudi Arabia. pic.twitter.com/6HxD7rB7VM— Jim McGrath (@jgm41) January 23, 2015
Meanwhile, President Barack Obama touted the U.S.-Saudi relationship "as a force for stability and security in the Middle East" and credited Abdullah with supporting that partnership in a statement. He also said he valued Abdullah's perspective and appreciated their "warm friendship."
Obama on the death of Saudi Arabia's King Abdullah pic.twitter.com/wa9UQ4JAbu— Brittany Levine (@brittanylevine) January 23, 2015
Abdullah is survived by more than 30 children from around a dozen wives.
Additional reporting by The Associated Press
Updated Jan. 22, 2015, 5:30 p.m. PT: Included historical information about the king's time in power as well as condolences from U.S. officials