ISLAMABAD - Pakistani officials commemorated Benazir Bhutto's birthday with plans to rename an airport after the slain former prime minister, build a monument on the site of her assassination and grant clemency to thousands of death row inmates.

Prime Minister Yousuf Raza Gilani announced the measures in a speech to parliament, which observed a minute of silence for Bhutto, who would have turned 55 on Saturday.

Bhutto, who was head of the Pakistan People's Party, was assassinated in a bombing and shooting attack outside a December election rally in the garrison town of Rawalpindi. The country was stunned by her death, and Bhutto's party went on to win February elections and form the new governing coalition.

Her birthday was marked in low-key ceremonies at her mausoleum in the town of Naudero, where dozens of sombre supporters gathered to offer prayers. Some carried large portraits of her and demanded the arrest of her killers.

Her widower and successor as party leader, Asif Ali Zardari, laid flowers at her grave and recited verses from the Qur'an, the Islamic holy book.

Gilani, a leader in Bhutto's party, used the occasion to recommend that President Pervez Musharraf clear the country's death row and commute all its death sentences to life in prison as a tribute to Bhutto. Musharraf was expected to approve the measure.

The mass commutation, which would not prevent future death sentences from being handed down, would be a major victory for human rights activists.

Earlier this week, New York-based Human Rights Watch said about 7,000 people _ nearly one quarter of all prisoners in Pakistan _ were awaiting execution. In 2007, 309 prisoners were sentenced to death and 134 were hanged, the group said.

Mahmoodul Hassan, an official at Adyala Jail near Rawalpindi _ where Gilani was repeatedly imprisoned throughout his political career _ said the death row prisoners rejoiced after hearing the prime minister's speech on television.

"They are happy, and they are thanking Benazir Bhutto, they are praising the government and the prime minister,'' he said.

Gilani also recommended that most prisoners, except those guilty of the worst crimes, have their sentences reduced by three months.

Akram Sheikh, a senior Pakistani lawyer, welcomed the move, saying a large number of prisoners would benefit from the amnesty. "The president is bound to give his approval on any such recommendation,'' he said.

The government also decided to rename Islamabad International Airport after Bhutto and to erect a monument at the spot where she was killed as a reminder that "here was a leader who gave her life for the rights of the people of Pakistan,'' Gilani said.

Bhutto's death shocked the world, fanning revulsion at rising militant violence as well as conspiracy theories that Pakistan's powerful spy agencies were involved. The previous government blamed Baitullah Mehsud, a Pakistani militant commander.

Zardari said Saturday he would lobby for the government's request for a United Nations inquiry into her assassination. Musharraf and the United States have opposed a UN investigation.

But Bhutto's party said the world body should investigate the killing given Mehsud's alleged links to al-Qaida and because of the huge political controversy surrounding the case.

Speaking in parliament, Gilani urged legislators to help fight terrorism that "deprives us of our leaders.''

"We will make Pakistan a safe haven for humanity and not for terrorists,'' Gilani said. "We will make this country a cradle of peace.''