Within less than a month, popular uprisings toppled the long-time presidents of Egypt and Tunisia, and revolts could spread to other Arab countries if they do not implement reforms quickly, analysts say.
"The Arab leaders are in a race against time: either they quickly adopt liberal changes, or they suffer the same fate as (the leaders) of Tunisia and Egypt," said Anwar Eshki, the director of the Middle East Institute for Strategic Studies in Jeddah, Saudi Arabia.
Egypt's president Hosni Mubarak, who resigned after being in power since 1981, and Tunisian president Zine El Abidine Ben Ali, who departed after ruling for 23 years on January 14, both bowed to unprecedented waves of popular protests.
Angered by injustice, unemployment and corruption, "the Arab citizen is not the same as he was two months ago" and "has proven he can bring down an Arab head of state after two or three weeks of demonstrations," said Paul Salem, the director of the Carnegie Middle East Centre.
Various Arab leaders, some of whom, such as Libyan leader Moamer Kadhafi, have been in power for over 40 years while many of those who have ruled with an iron fist have suddenly announced social security measures and political reforms.
The popular uprisings in those two countries "will have repercussions throughout the region" and the United States, which encouraged change in Tunisia and Egypt, will try to do the same in other Arab countries, said Saleh al-Qallab, a former Jordanian information minister.
"Who is next? No one can predict," he said, adding that this excludes Saudi Arabia, where "the process of reforms initiated by King Abdullah is moving slowly due to the weight of tradition and religion."
Eshki echoed that assessment, saying that "the United States will seek to avoid sudden change in the Gulf monarchies that could disrupt oil supplies to the world economy," but Washington "will advise them to engage in reforms and accelerate their implementation."
But he added that "the winds of change will blow on these (Gulf) countries. And if the leaders do not take the initiative, their people will."
The uprisings in Tunisia and Egypt, which were initiated and led by young people using the social networking site Facebook and micro-blogging site Twitter, have showed the limits of Islamist activism, which Arab regimes have used as a scarecrow to ward off calls for reform, Salem said.
"Without adhering to an ideology," the uprisings have succeeded where Islamist movements have failed for decades, during which "they were presented or presented themselves as the only alternative to repressive Arab regimes," he said.
Salem added however that Mubarak's fall, in the eyes of Riyadh, "exacerbates the imbalance of power in the favour of Iran," which wants "an Islamic Middle East," and sees the departure of the Egyptian president as "the failure of the United States and Zionism in the region."
"The alliance of the Arab countries and the United States will weaken in favour of a degree of autonomy on the Turkish model, but these countries have no choice but to remain in the American fold," Salem said.