Pakistan president-elect Asif Ali Zardari was set to be sworn in to office Tuesday, completing a rise to power considered unthinkable before the slaying of his opposition leader wife Benazir Bhutto.
Zardari secured a large win in a poll among lawmakers Saturday and will become the 14th president in the short but often turbulent history of the world's only nuclear-armed Islamic state and frontline US "war on terror" ally.
The inauguration will take place in a closely-guarded ceremony at Aiwan-i-Sadr (President House) in Islamabad around 1pm (0700 GMT), officials told AFP.
The Afghan president Hamid Karzai will attend the event, in which Pakistan's chief justice will administer the oath as government leaders, military top brass, judges, diplomats and high-ranking civil servants look on.
A guard of honour comprising the three armed forces will then welcome Zardari on the lawn of the presidential palace, completing a spectacle expected to be broadcast live to the nation.
"It is a very significant day in the history of Pakistan and it is the victory of the people and the mission of Benazir Bhutto shaheed (martyr)," said Farzana Raja, an MP and senior Zardari aide ahead of the ceremony.
"The dream that she saw for the people of Pakistan has come true," she added, reflecting on Bhutto's plans for the country before her assassination at a campaign rally in December 2007.
Security around President House, which is situated in the already high-security zone of Islamabad, has been further fortified ahead of the inauguration, officials said.
Zardari, who has said previously that he expects to be targeted by extremists such as those who killed his wife, will take control of a country riven by Islamic militancy and economic turmoil.
He succeeds Pervez Musharraf, the former army general who resigned on August 18 under threat of impeachment.
The 53-year-old takes office amid mounting international concern about the stability of Pakistan, which under Musharraf backed the United States after the September 11 attacks in 2001 and in its subsequent invasion of Afghanistan.
Billions of dollars of aid flowed to Islamabad in return.
However, around 1,200 people have died in bombings and suicide attacks across the country in the past year, in violence attributed to a backlash against Musharraf's support for the United States.
The violence was underscored during Saturday's election when a suicide car-bomber rammed a police checkpost, killing 33 people and wounding more than 80 in the northwestern city of Peshawar.
The United States restated Pakistan's strategic importance ahead of Zardari's inauguration, with President George W. Bush set to describe the country as a major war on terrorism battleground, such as Afghanistan or Iraq.
"They are all theatres in the same overall struggle. In all three places, extremists are using violence and terror in an attempt to impose their ideology on whole populations," Bush said in an advance text released late Monday.
His message came amid media reports of multiple strikes inside Pakistan recently by US or international troops based in Afghanistan, which accuses its neighbour of abetting or at least turning a blind eye to cross-border violence.
"Defeating these terrorist and extremists is in Pakistan's interest because they pose a mortal threat to Pakistan's future as a free and democratic nation," Bush said in the prepared remarks.
Zardari will speak to reporters later Tuesday and is expected to outline his vision for Pakistan, including his plans to counter extremism and turn around an economy beset by rampant inflation and a plunging stock market.
As co-chairman of the Pakistan People's Party (PPP), Zardari already heads a fragile coalition government which, although still in office, recently lost the backing of former prime minister Nawaz Sharif's party.
As president, Zardari gains the right to dismiss governments and appoint leaders of the military, which has ruled Pakistan for half of its 61-year existence.