A suicide bomber blew himself up Saturday in a wedding hall in northern Afghanistan, killing at least 23 people including a prominent warlord-turned-politician and three Afghan security force officials, in an attack that deals a setback to efforts to unify the nation's ethnic factions, Afghan officials said.

Ahmad Khan Samangani, an ethnic Uzbek and anti-Soviet guerrilla leader in the 1980s who later became a member of parliament, was welcoming guests to his daughter's wedding when the explosion occurred in Aybak, the capital of Samangan province.

President Hamid Karzai said 23 people were killed and about 60, including government officials, were wounded in the attack, which he condemned and said was "carried out by the enemies of Afghanistan." He ordered a team from Kabul to fly to the northern province to investigate the bombing.

No one has yet claimed responsibility for the blast. But in announcing their spring offensive on May 2, the Taliban said they would continue to target those who back the Karzai government and the U.S.-led international military coalition.

Karzai needs the minority groups — loosely known as the Northern Alliance — to back his efforts to reconcile with the Taliban. But minorities already worry that Karzai, a Pashtun, will make too many concessions to their Taliban enemies to achieve a peace deal to end the war. Whatever support for peace talks that Karzai has won from minority groups is likely to erode if militants continue to pick off their leaders one by one.

It was the most recent in a month-long string of deadly attacks around the country.

On June 22, heavily armed Taliban fighters attacked a lakeside hotel north of Kabul and killed 18 people during a 12-hour standoff with security forces. Two days earlier, a suicide bomber killed 21 people, including three U.S. soldiers, at a checkpoint in a crowded market in the eastern city of Khost.

The violence threatens to undermine international hopes of an orderly handover to Afghan forces by the end of 2014.

Separately, NATO said two of its service members were killed Saturday in eastern Afghanistan — one in an insurgent attack and the other as a result of a non-battle related injury. No other details were provided. So far this year, 235 NATO service members have died in Afghanistan.

In western Afghanistan, Abdul Salam Rahimi, the mayor of Shindand district in Herat province, was assassinated Friday evening by two gunmen on a motorbike, authorities said. A civilian, who was injured in the shooting, later died at a hospital.

Mohammad Nawab Sherzai, criminal investigations director in Aybak who was helping provide security for the wedding, said most of the local guests had already gathered on the second and third floors of the three-story wedding hall when the morning explosion occurred. Samangani and other relatives and elders had moved to the first floor to welcome additional guests arriving from Mazar-i-Sharif, the capital of neighboring Balkh province.

"Suddenly, the attacker, who was among the guests from Mazar-i-Sharif, got very close to Samangani. He detonated his suicide vest," Sherzai said. "It was a big explosion. There were bloody bodies all around the first floor. The explosion was so strong. There were people even on the third floor who were wounded."

"Everybody was running in different directions. For about 10 minutes, nobody knew what was happening," he said. "There was dark smoke all around. After about 10 minutes, the people were able to see the bodies and start helping with the wounded."

The three Afghan security force officials killed were Afghan National Police Gen. Sayed Ahmad Sameh, the commander for the western region and a relative of Samangani; Gen. Mohammad Khan, the intelligence chief in the province; and Mohammadullah, an Afghan National Army division commander who uses only one name, which is common in Afghanistan.

The wounded included a lawmaker from Balkh province and a former governor of Sar-e-Pul province.

After the blast, shattered glass, blood and other debris and covered the site and the injured were helped from the scene. Afghan Army helicopters and ambulances ferried some of the wounded from rudimentary medical facilities in Aybak to Mazar-i-Sharif, which has larger hospitals. Dead bodies were piled into the back of Afghan security force vehicles and taken from the wedding hall, which has a facade of pillars painted a festive light green and pink. The wedding never occurred.

Samangani became famous during Afghanistan's fight against the Soviets, who left the country in 1989 after a 10-year occupation. He became a member of parliament last year and was considered a key leader in Samangan and northern Afghanistan. He was a former military commander under Northern Alliance general Abdul Rashid Dostum, a powerful Uzbek warlord. Samangan, a province with about 350,000 people, has in the past been politically split between ethnic Tajik and Uzbek leaders.

The withdrawal of most foreign troops by the end of 2014 has spawned fears the country will descend into civil war when foreign troops leave.

To prevent that, Karzai needs the Northern Alliance to back his efforts to reconcile with the Taliban. That's because, while Pashtuns make up 42 percent of the population, collectively the minority Tajiks, Hazaras, Uzbeks and other smaller groups outnumber them. Without minority support, the country risks a de facto partition into a Pashtun south and a "minority" north.

The Taliban have assassinated a number of Northern Alliance and other minority leaders in recent years.

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Gen. Daud Daud, an ethnic Tajik, who oversaw police activities in nine northern provinces, was killed in May 2011 when a Taliban suicide bomber wearing a police uniform blew himself up inside a heavily guarded compound as top Afghan and international officials left a meeting. Daud had also served as governor of Takhar province in the north, deputy interior minister for counternarcotics and was a former bodyguard of Ahmad Shah Massoud, the charismatic Northern Alliance commander who was himself killed in an al-Qaida suicide bombing two days before the Sept. 11, 2001, attacks.

Other assassinations include the Takhar provincial police chief, Gen. Shah Jahan Noori, who died in the same blast as Daud. Mohammad Omar, the governor of neighboring Kunduz province in the north, was assassinated in October 2010 inside a mosque. Gen. Abdul Rahman Sayedkhili, the provincial police chief of Kunduz province, was killed by an insurgent bomber in March 2011. A month later, a suicide bomber killed Gen. Khan Mohammad Mujahid, who was police chief in the Taliban stronghold of Kandahar province in the south, but was aligned with the Northern Alliance.