The attacker embraced MP Ahmad Khan, a former militia commander, in front of wedding guests before detonating the explosives strapped around his waist, a security forces spokesman said.
President Hamid Karzai’s office said in a statement 17 people were killed and around 43 wounded, revising an earlier statement that said 23 were killed in the attack in Aybak, capital of normally peaceful Samangan province.
“Latest reports indicate that 17 people were killed and about 43 others were wounded,” the statement said.
Provincial intelligence chief Mohammad Khan was among those killed at the celebration attended by other high-ranking government officials.
The statement blamed the “terrorist” attack on the “enemies of Afghanistan”, a term used by Afghan officials to refer to the Taliban.
Karzai also appointed a delegation to investigate the attack.
An ethnic Uzbek, Khan was a militia commander during the decades of conflict in Afghanistan, when his forces held sway in the area.
There was no immediate claim of responsibility for the attack. Zabiullah Mujahid, a purported Taliban spokesman, told AFP that he was “unaware” of an attack by the militant group in northern Afghanistan.
Witnesses at the scene told AFP the windows of the two storey wedding hall were shattered and blood-stained turbans, shoes and clothes could been seen around the hall.
The attacker apparently disguised himself as a guest and blew himself up at the entrance of the hall, where high-ranking local officials were welcoming guests.
Northern Afghanistan is relatively peaceful but suffers sporadic violence.
The attack in Samangan suggests an emboldened Taliban insurgency spreading to the north from the south and east, where they traditionally hold sway.
But the Islamic Movement of Uzbekistan (IMU), a key ally of Al-Qaeda, is also active in Afghanistan’s northern provinces.
In March, Afghan and international forces killed Makhdum Nusrat, a senior IMU leader in Afghanistan, in Faryab province, to the west of Samangan. The following month a suicide attack in Faryab killed 12 people, mostly civilians.
Last year, a Taliban suicide attack killed General Daud Daud, a regional police commander and once Afghanistan’s most powerful anti-drug czar, in Taloqan, the capital of Takhar province, also in the north.
The wedding attack came the day after a provincial women’s affairs official in Laghman, east of Kabul, was killed and her husband and daughter critically wounded when a magnetic bomb attached to her vehicle exploded, police said.
Laghman provincial government spokesman Sarhadi Zwak blamed Taliban insurgents for that attack.
The Taliban have waged a bloody insurgency since their ouster from power following a US-led invasion shortly after the September 11, 2001 attacks in the United States.
Attacks by the Taliban kill hundreds of civilians every year, but many Afghans worry that security will worsen, or that civil war could reignite, when foreign forces pull out.
There are currently around 130,000 international troops in Afghanistan and all NATO-led combat forces are due to leave by the end of 2014.