In reversal, Mubarak resigns

Mass cheering erupted in Cairo on Friday after Egyptian President Hosni Mubarak left office following weeks of protests against his government. 

Jubilation broke out in Tahrir Square, the epicenter of the protests, after the Egyptian government announced Mubarak was stepping down. He had left Cairo earlier in the day for the resort city of Sharm el-Sheikh on the Red Sea, effectively removing himself from office.

Mubarak's departure comes the day after he made a defiant speech that left Washington and the throngs of protesters wondering whether he was really leaving. He had vowed to remain in office until September elections.

President Obama was notified of Mubarak's decision earlier Friday during a meeting in the Oval Office. He then watched television coverage of the jubilant scene in Cairo for several minutes just outside the Oval Office.

Obama is expected to make an on-camera statement on the new developments at 3 p.m., according to the White House.

Vice President Biden, speaking at an event in Kentucky, called Mubarak's resignation a "pivotal moment in history" and called on members of both parties to speak with one voice as Egypt makes its political transition — a transition with repercussions in the Middle East and well beyond.

In a statement, Senate Majority Leader Harry ReidHarry ReidReid sums up 114th Congress as 'a flop' Reid: GOP treated Obama with 'unprecedented disrespect' Abortion rights group ads tie vulnerable GOP senators to Trump MORE (D-Nev.) said the United States would be watching that  transition closely.

“I am pleased that President Mubarak has heard and heeded the voice of the Egyptian people, who have called for change," Reid said. "It is crucial that Mubarak’s departure be an orderly one and that it leads to true democracy for Egypt, including free, fair and open elections. 

"We caution all sides against violence during this transition, and we will be watching the situation closely. We wish the Egyptian people the best in their next steps toward determining their own future under a democratic process.”

The chairman of the Senate Foreign Relations Committee, John KerryJohn KerrySenators press State Department on 'plan B' in Syria Russian general says Moscow is ready to restart Syria talks Overnight Defense: Congress overrides Obama 9/11 veto | Pentagon breathes easy after funding deal | More troops heading to Iraq MORE (D-Mass.), said the United States "must help Egyptians turn this democratic moment into a process that builds a government responsive to economic needs as well as demands for freedom."

"What happens next will have repercussions far beyond Egypt’s borders," he said in a statement.

Obama offered his toughest comments to date on the situation after Mubarak's defiant speech on Thursday night, in which the Egyptian leader said he would pass some of his powers to Vice President Omar Suleiman.

Obama said Egypt's government needed to respond to protesters and make clear its intentions for an immediate transition. The statement did not mention Mubarak by name.

In Mubarak's absence, the Egyptian military promised to carry out constitutional reforms, according to a statement. 

The announcement Friday of Mubarak's resignation came from Suleiman, who said the Egyptian military is now charged with certain governmental responsibilities. 

"In the name of God the merciful, the compassionate, citizens, during these very difficult circumstances Egypt is going through, President Hosni Mubarak has decided to step down from the office of president of the republic and has charged the high council of the armed forces to administer the affairs of the country," Suleiman said. "May God help everybody."

Opposition figure Mohammed ElBaradei, the Nobel laureate and former head of the International Atomic Energy Agency, called Friday "the greatest day of my life," according to The Associated Press.

"The country has been liberated after decades of repression," he said.

Other lawmakers also weighed in, with Sen. John McCainJohn McCainOvernight Defense: Congress overrides Obama 9/11 veto | Pentagon breathes easy after funding deal | More troops heading to Iraq McCain comments won't derail Bergdahl case Senators already eyeing changes to 9/11 bill after veto override MORE (R-Ariz.) saying Mubarak's "last action in office was in the best interest of the country he loves."

McCain said representatives from Egypt’s opposition, including pro-democracy parties, must be included in the transition government. Before any elections, he said, "Egyptians must be free to exercise their universal rights peacefully – to speak and express themselves without interference, including over the internet; to organize independent political parties; to register candidates of their choosing for office; and to participate in elections that are free and fair by international standards."

Sen. Bill NelsonBill NelsonElection-year politics: Senate Dems shun GOP vulnerables Overnight Finance: Senate rejects funding bill as shutdown looms | Labor Dept. to probe Wells Fargo | Fed to ease stress test rules for small banks Overnight Energy: Judges scrutinize Obama climate rule MORE (D-Fla.), who said he was the first senator to call for Mubarak's resignation, called the news "truly monumental."

"President Mubarak rightly honored the Egyptian people’s calls for freedom," he said in a statement. "All nations must now support an orderly, peaceful transition to democracy. We hope the first steps of the new government will be to guarantee free and fair elections as soon as possible, while also keeping the peace with all of Egypt’s neighbors, including Israel."

—Sam Youngman contributed.

This post was last updated at 1:35 p.m.