A well-known Afghan politician and around 20 other people have been killed in a suicide attack in the northern province of Samangan, police say.Ahmad Khan Samangani, an ethnic Uzbek MP, was attending a wedding party for his daughter in the provincial capital, Aybak, when the blast happened.The attacker, posing as a guest, embraced Mr Samangani before detonating his explosives, a witness said.A Taliban spokesman denied involvement in the attack.Ahmad Khan Samangani was a commander in the mujahideen militia during Afghanistan's civil war in the 1980s.He was known as a supporter of President Hamid Karzai and a rival of Gen Abdul Rashid Dostum, a powerful civil war commander in the north and currently one of Afghanistan's most prominent Uzbek politicians, the BBC's Bilal Sarwary, in Kabul, says.Mr Samangani became a member of parliament last year, replacing one of several sitting MPs expelled by the Independent Electoral Commission for alleged electoral fraud in the 2010 parliamentary election.President Hamid Karzai has appointed a team to investigate the attack. A statement from his office blamed "enemies of Afghanistan".'Notorious'The hall where the wedding was taking place was packed with about 100 people, a witness said.In addition to those killed, more than 40 other people were wounded in the attack, according to police.Ghulam Mohammad Khan, the criminal director of the provincial police, told Associated Press that the dead included provincial intelligence chief Mohammad Khan.A senior regional police commander related to Mr Samangani was among those injured, he added."We don't have a hand in this issue," Taliban spokesman Zabiullah Mujahid told the Reuters news agency."Ahmad Khan was a former commander of the mujahideen, he was notorious and many people could have had problems with him," he said.Northern Afghanistan is relatively peaceful compared to the east and south of the country, where militant attacks are frequent.The attack in Samangan comes a day after a prominent female Afghan politician was killed in a bomb attack in eastern Laghman province.The politician, Hanifa Safi, was the provincial head of the Afghan ministry of women's affairs and was known as a leading advocate of fair treatment for women.Many Afghans fear that attacks, particularly by the Taliban, will increase after foreign forces leave.The 130,000-strong Nato-led force is scheduled to end combat duties in 2014.