LAHORE, Pakistan (CNN) -- Pakistan's President Gen. Pervez Musharraf, under pressure to end emergency rule that critics say he is using to retain power, will step down as the country's military leader Wednesday, his spokesman has told CNN.
Pakistan President Gen. Pervez Musharraf has been under pressure to lift a state of emergency.
Musharraf will take an oath of office for a third presidential term Thursday, the spokesman added.
The announcement came as former prime minister Nawaz Sharif, ousted by Musharraf in a 1999 coup and banished to Saudi Arabia, returned to the country to register for forthcoming elections, ruling out an alliance with the president.
Presidential spokesman Brig. Gen. Rashid Quershi told CNN that the date for Musharraf's army exit was set Monday after the federal government approved an October parliamentary vote that handed him another five years in power.
The vote had faced a legal challenge because Musharraf's army role was seen as unconstitutional. He has been accused of using the emergency to purge Pakistan's judiciary of opponents to ensure the vote met with full approval.
Musharraf has repeatedly tried to assuage critics, both home and abroad, by pledging to stand down as army chief -- but there were fears that he would renege on the promise as he has done in the past.
The news of his imminent change to civilian status drew a muted reaction from the United States, which has repeatedly called on Musharraf to remove his uniform.
"Musharraf has committed to stepping down from the army, and we urge him to honor his commitments," National Security Council spokesman Gordon Johndroe said.
The United States has also called on Musharraf to end the state of emergency -- which opponents say amounts to martial law -- before elections scheduled for January 8.
But Musharraf has rejected calls from Western countries, who count the nuclear-armed country as a major ally in efforts to combat terrorism, to end the emergency, saying he needs it to safeguard the upcoming vote from extremists.
Qureshi said Musharraf will make farewell visits to the army, air force and navy headquarters Tuesday and Wednesday before standing down.
Musharraf has named Lt. Gen. Ashfaq Kiyani -- a former head of Pakistan's Inter Services Intelligence agency -- to take his place as military chief.
Arif Nizami, editor of the Pakistani daily, The Nation, said Kiyani is generally regarded as "in the same mold as General Musharraf."
"Musharraf has chosen a successor very carefully who will continue his policies and he will be as pro-western as General Musharraf is," Nizami told CNN International last month.
However, he pointed out that "once the army chief is there, he is his own man and you can't be 100 percent sure what kind of policies he'll pursue."
Musharraf, who as army chief led the coup that ousted Sharif, has been reluctant to relinquish his military position because his power base resides in the army. His commitment to stepping down is unlikely to satisfy the concerns of Pakistan's opposition.
Sharif, who spent seven years in abroad after taking exile in return for an amnesty on convictions of corruption and hijacking, returned to Pakistan Sunday, ending seven years in exile in. He had tried to return in September, but was deported by Pakistani authorities.
While Sharif has repeatedly said he would refuse to participate in the January elections if they are held under the state of emergency, his Pakistan Muslim League party hedged its bets by filing papers by Monday's deadline.
Observers believe Sharif wants to keep all options open, including a possible run for the prime minister post in the event that another opposition party decides to participate in the upcoming elections.
He said Monday he will meet with other opposition party leaders in the coming days to discuss forming a unified front against the emergency that has been decried as a tool to crackdown on opponents since it was imposed on November 3.
Speaking to CNN before departing Saudi Arabia Sunday, Sharif said he has refused to discuss a power-sharing agreement with Musharraf despite overtures from the Pakistani leader.
"Mr. Musharraf, the president of Pakistan, tried to meet me over the last two months ever since I was deported from Pakistan," Sharif said. "I said there is no point in talking because it would not serve any purpose because he is heading into a different direction.
"I am for democracy and I am for the rule of law for the restoration of the constitution."
Pakistani police launched a crackdown on Sharif supporters ahead of his arrival, arresting several hundred at their homes and stopping hundreds more who were traveling to Lahore to welcome him, authorities and eyewitnesses told CNN.
When former prime minister and opposition leader Benazir Bhutto returned to Pakistan in October after eight years in self-imposed exile, her motorcade was targeted in a sucidide attack that killed at least 136 people. She was unharmed.
Sharif -- who leads the opposition party Pakistan Muslim League -- said he had been talking to Bhutto "trying to find common ground" in uniting the opposition to Musharraf's government.
"We both have been interacting over the past few days, so let's see what comes out of it," Sharif said.
Sharif, like other opposition leaders, was highly critical of Bhutto for discussing a power-sharing government with Musharraf. Those talks ended when Musharraf imposed the emergency.
Sharif said that while his alliance -- the All Pakistan Democratic Movement (APDM) -- is preparing to participate in the January elections, they will only take part if Musharraf withdraws the emergency declaration and release opposition members who have been jailed.
"Everything that was done must be reversed and drawn back completely," he said. "Just withdrawing emergency will not be enough. You must have a level playing field for free and fair elections."
Asked if he could ever agree to a power-sharing deal with Musharraf as president and he as prime minister, Sharif answered, "No, no, no, no question."
Cricketer-turned-opposition leader Imran Khan told CNN last week that Bhutto is the only hold-out to a unified boycott of the election. "All the other opposition parties have a complete consensus that this will be the most fraudulent election in the history," Khan told CNN days after he was released from jail.
"The only question mark is Benazir Bhutto. We don't know whether she'll boycott or whether she'll participate."
Khan launched a hunger strike to protest Musharraf's dismissal of Supreme Court justices after he and hundreds of other opposition figures were jailed in the wake of the emergency order. His Movement for Justice Party campaigns for an independent judiciary in Pakistan. E-mail to a friend
CNN's Zein Basravi in Lahore contributed to this report