Updated at 12:17 p.m.

Supporters of Egypt's revolution logged another victory Thursday with the resignation of Ahmed Shafiq, the prime minister appointed by former President Hosni Mubarak just before he was toppled by a popular uprising last month.

The Supreme Council of the Armed Forces, which is ruling the country until new elections are held, announced on its Facebook page Thursday it had accepted Mr. Shafiq’s resignation and appointed former transportation minister Essam Sharaf to form a new government in his place.

Shafiq’s ouster demonstrates that the armed forces are eager to maintain stability and recognize that keeping Mubarak associates in office would have the opposite effect. It is another manifestation of Egyptians' newly discovered people power as they take to the streets to demand far-reaching change beyond the ouster of Mubarak.

But while protesters welcomed Shafiq's departure, many were skeptical about his low-profile replacement and vowed to keep up the pressure on the government.

“It’s good news, but it’s not enough,” says Layla Maged, a protester in Tahrir Square taking refuge from the hot sun in a large tent she shares with several friends. A tarp covered the floor and she sat on a blanket. A tent next door proclaimed itself the Revolution Villa.

“We still need all the people arrested since Jan. 28 to be released, we need to get rid of the Emergency law, state security, and the local governors need to be gone," she said, adding that she would stay until those demands had been met. "Basically, we need to clean up the government.”

Debate over whether to stay in Tahrir

Shafiq’s resignation came after his appearance on a popular satellite television channel Wednesday evening was widely lambasted, and a day before a large protest planned to call for his ouster. It also comes just days after Tunisia's prime minister stepped down following fresh protests for more robust change turned deadly in that North African country, which was the first revolution to ignite the wave of popular revolt across the Arab World.

While the move appeared to be an effort by the Egyptian military to deflate Cairo protests before they swelled again, it is unclear whether Egyptians will take down the tent city in Tahrir square, the epicenter of the revolution, or will stay until their other demands are met.

In the square Thursday afternoon, groups gathered to debate the strategy. Dozens crowded around several men who argued about whether to go home, as some opposition groups have called on them to do. Many who had pitched their tents, such as Ms. Maged, appeared determined to stay.

“I am so happy,” says Abdullah AlFakharany, a protester who has been in Tahrir nearly every day since the movement began Jan. 25. “Finally we changed something. But I think people will not leave Tahrir Square because state security is still there, the Emergency Law is still in effect. There are still things to change.”

Too close to Mubarak

Protests had gone on for weeks calling for the ouster of Shafiq, a former Air Force officer and head of Egypt Air. He was seen as a Mubarak loyalist, and his early refusal to call Egypt’s movement a revolution infuriated protesters. In past weeks, some wore buttons that said “Shafiq is the new Mubarak.”

Wednesday night he appeared in a discussion on a popular satellite channel and only further enraged many Egyptians by defending Egypt’s state security forces and suggesting Tahrir Square become like Hyde Park in London.

Egypt’s attention will now be focused on Sharaf, who has not cut a very high profile. He served as transportation minister under Mubarak from 2004 to 2006 but criticized the regime when he resigned. In a bio on the website of Purdue University College of Engineering, where he earned masters and doctorate degrees, his tenure at the ministry is described as a time of modernizing Egypt’s transportation infrastructure. After he left the government, he became a professor at Cairo University.

He was reported to have joined the protesters in Tahrir Square before Mubarak’s ouster, and to have been an early supporter of the movement. But protesters in Tahrir on Thursday afternoon were still trying to figure out exactly who he was. Some were initially suspicious of the fact that he had been a member of Mubarak’s government.

“I don’t know Essam Sharaf, but he was from the previous government,” says Mahmoud Metwaly. “I don’t know a lot of information about him. But maybe the Army chose him to be the new prime minister, and I don’t trust the Army. I will come again to protest tomorrow.”

Others tried to convince people like Mr. Metwaly that Sharaf was trusted by the coalition of young leaders who have been meeting with the military council, and that they had suggested him as a possible replacement for Shafiq.

“I have nothing against him, but I don’t know him,” says Maged. Many, like her, may adopt a wait-and-see approach.

Protesters want even more change

A key indication will be what kind of cabinet he appoints, says independent Egyptian analyst Ibrahim El Houdaiby. He calls Sharaf a respected figure untainted by corruption and without strong connections to Mubarak’s regime. Protesters will want to see him get rid of the Mubarak-era cabinet ministers that remained in Shafiq’s cabinet.

“We have to see serious changes in the ministry of interior, ministry of foreign affairs, and ministry of justice,” says Mr. Houdabiy. “We need to see changes not only in people, but in policies. … We have to be very, very careful. We’re moving in the right direction but fairly slowly. We need to see changes in the state security apparatus and ministry of interior. We need to see a complete restructuring of the police.”

Indeed, the restructuring of the police and security apparatus, long a tool of Mubarak’s repression, will become a key demand among the people, now that their first demand has been met. They will also focus on securing the release of political prisoners, an end to the emergency law, and the use of military courts for civilians. Human Rights Watch reported this week that the Army has continued to use the military courts to quickly convict civilian protesters without fair trials since it took control of Egypt Feb. 11.

A military court on March 1 convicted protester Amr Abdallah Al Bahari of assaulting a soldier, a charge witnesses deny, after he was arrested only three days before.