Pakistan is observing the fifth anniversary of the assassination of former prime minister Benazir Bhutto, with her son expected to launch his political career to mark the day.
Bhutto, twice elected prime minister, was killed in a gun and suicide attack after an election rally in Rawalpindi, the headquarters of Pakistan's army, on December 27, 2007.
No one has ever been convicted of her murder, but the ruling Pakistan Peoples Party is expected to release names of people it says assassinated Bhutto.
Al Jazeera's Kamal Hyder, reporting from the capital Islamabad, said the question of why the names were being released now had been asked by many in Pakistan.
He said the names were being released despite the fact that the PPP information minister and the Bhutto family had said they believed the former prime minister was killed the Pakistani Taliban.
Thousands are expected to gather at the family mausoleum at Larkana in the southern province of Sindh where Bilawal Bhutto Zardari, the son of Benazir and of President Asif Ali Zardari, is to make his first major public speech.
But the 24-year-old Bilawal will be too young to stand if elections go ahead as expected in the spring, the AFP news agency reported. The lower age limit is 25.
Bilawal, co-chairman of the PPP with his father, in May accused former military ruler Pervez Musharraf of "murdering" his mother by deliberately sabotaging her security.
But the Musharraf regime blamed the assassination on Pakistani Taliban chief Baitullah Mehsud, who denied any involvement and was killed in a US drone attack in August 2009.
"Let us resolve to defeat the forces of extremism and terrorism and work for the progress and prosperity of the country," Bilawal said in a statement.
A Pakistani political analyst said Bilawal had embarked on a political career.
"It appears to be the formal launching of Bilawal Bhutto Zardari into politics," Hasan Askari told AFP.
"Bilawal has symbolic value in the Bhutto family and Zardari would like this link to be used as symbolism in the election."
The Bhutto family has been a force in Pakistani politics for almost all of the country's 65-year history, and the Bhuttos are an almost ever-present element in the rhetoric of PPP leaders, who frequently eulogise the party's two "martyrs" as champions of the common man's struggle against a repressive "establishment".
Benazir's father Zulfikar Ali Bhutto led the country from 1971 until he was ousted in a military coup in 1977. He was hanged in 1979 after being convicted of authorising the murder of a political opponent.
With a general election due in the spring, analysts say the ruling PPP is eager to introduce a third generation of the dynasty to the public.
As head of state President Zardari, who came to power in elections held a month after his wife's murder, is barred from leading the PPP election campaign. He is also hugely unpopular, tainted by years of corruption allegations.
Prime Minister Raja Pervez Ashraf said the country should "shun prejudices and maintain unity" to pay homage to Benazir.