Saudi King Salman on Tuesday ordered that women be allowed to drive cars, ending a conservative tradition seen by rights activists as an emblem of the Islamic kingdom's repression of women.

The kingdom, the birthplace of Islam, has been widely criticized for being the only country in the world that bans women from driving, despite gradual improvement on some women's issues in recent years and ambitious government targets to increase their public role, especially in the workforce.

Despite trying to cultivate a more modern image in recent years, the driving ban had been a longstanding stain on Saudi Arabia's international image.

The royal decree ordered the formation of a ministerial body to give advice within 30 days and then implement the order by June 24, 2018, according to state news agency SPA.

It stipulated that the move must "apply and adhere to the necessary Sharia standards," referring to Islamic law. It gave no details but said a majority of the Council of Senior Religious Scholars, Saudi Arabia's top clerical body, had approved its permissibility.

An hour after the official announcement in Saudi Arabia, a jubilant Saudi ambassador to Washington, Prince Khaled bin Salman, said it was "[a] historic and big day in our kingdom."

Positive reactions quickly poured in from inside the kingdom and around the world, with the US State Department welcoming the move as "a great step in the right direction."

For more than 25 years, women activists have campaigned to be allowed to drive, defiantly taking to the road, petitioning the king and posting videos of themselves behind the wheel on social media. The protests brought them to arrest and harassment. Activist Manal al-Sherif, who was arrested in 2011 after a driving protest, took to Twitter following the king's announcement to express her relief. "Today, the last country on earth to allow women to drive... we did it," she wrote.

In Saudi Arabia, a top Arab ally of the United States, women are legally subject to a male guardian, who must give approval to basic decisions they make in fields including education, employment, marriage, travel plans and even medical treatment.

Women in the kingdom are also bound by law to wear long robes and a headscarf and require the consent of a male guardian for most legal actions.

Prince Khaled, the ambassador, said women would not need permission from their guardians to get a license or have a guardian in the car and would be allowed to drive anywhere in the kingdom, including the Islamic holy cities of Mecca and Medina.

Women with a license from any of the Gulf Cooperation Council countries would be allowed to drive in Saudi Arabia, he added. He said the Interior Ministry would have to decide whether they could be professional drivers.

The position of Saudi women gradually improved under late King Abdullah and since King Salman took over in 2015, the kingdom has been opening more areas for women through the government's modernizing reforms.