A homicide bomber killed 16 people and wounded at least 23 others Friday in a busy city square in western Afghanistan, while near Kabul a powerful former warlord narrowly escaped an assassination attempt, officials said.

The attacks came a day after Afghan President Hamid Karzai took the oath of office for a second term amid escalating violence across the country. Karzai said he has put national reconciliation with Taliban insurgents at the top of his agenda.

Lawmaker Abdul Rasul Sayyaf, a former Northern Alliance leader who has been accused by Human Rights Watch of war crimes, was in a convoy with his bodyguards when a remote-controlled bomb hidden in an irrigation canal beside the road exploded in the Paghman district north of the Afghan capital, said district chief of police Abdul Razaq.

One car in the convoy was destroyed, and Razaq said five of Sayyaf's bodyguards had been killed. Sayyaf himself was not injured.

In the homicide bombing earlier Friday in western Afghanistan, a bomber on a motorcycle blew himself up about 55 yards from the Farah provincial governor's compound in a crowded square, said Gov. Rohul Amin. The dead included two children and a police officer, he said.

Afghan police shouted "Stop! Stop!" at the motorcyclist before he detonated the explosives, provincial police chief Gen. Mohammad Faqir Askar said. It was unclear what the bomber was targeting.

Dr. Shir Agh Asas at the hospital in Farah city said several children also were among the wounded.

"These days Taliban are causing high casualties because the foreign forces and Afghan forces have been conducting operations against the insurgency in the region," Askar said.

An operation three days ago in another part of the province killed five insurgents, including a Taliban commander and a bomb-maker, Askar said.

There was no immediate claim of responsibility for either of Friday's attacks.

Sayyaf was a key U.S.-backed mujahedeen leader during the 1980s invasion of Afghanistan by the Soviet Union. His group was known for its close links to Arab fighters, including Osama bin Laden. He controlled the interior ministry when the mujahedeen ruled Afghanistan between 1992 and 1996, when their bitter internecine fighting led to the Taliban takeover in 1996.

Sayyaf was close to slain Northern Alliance leader Ahmed Shah Masood and opposed to the Taliban. When the Northern Alliance, backed by U.S. forces, toppled the Taliban regime after the Sept. 11, 2001, attacks for hosting Al Qaeda in Afghanistan, Sayyaf became a powerful figure in Kabul once more.

He has since been elected to Parliament and has close ties to Karzai, campaigning for him during the August presidential elections.

On Thursday, Karzai invited insurgents to lay down arms.

"We invite dissatisfied compatriots, who are not directly linked to international terrorism, to return to their homeland," he said.

Karzai also set a five-year timetable for the Afghan security forces to take the lead in defending the nation, a goal that would allow international forces to take on more of a support role.

As the inaugural ceremony took place in Kabul on Thursday, a homicide bomber killed two U.S. service members in the southern province of Zabul, local officials and NATO said. Hours later, another homicide bomber blew himself up in a busy marketplace in another province, killing 10 civilians, including three boys, and wounding 13 other people.

Also Friday, three civilians were wounded by a roadside bomb in Khost province, according to Wazir Pacha, deputy police chief of Khost.

Separately, NATO said Afghan and international forces killed a man in Takhar province in northern Afghanistan on Friday believed to be an operative with the Islamic Movement of Uzbekistan who was responsible for financing militant activities and transporting foreign fighters into the region. The man was killed during a search of a compound in rural Bangi district, it said.

According to NATO, there has been an increase in the number of Uzbek fighters in the ranks of the Taliban in northern Afghanistan from the Islamic Movement of Uzbekistan.