Nairobi - An opposition politician was hacked to death at his home in central Tanzania on Thursday night, police said on Friday, as his party described the murder as a "political assassination."Godfrey Luena, of the Chadema party, was the elected head of the small Namawala municipality in the central Morogoro Region. He was the second party official to be killed in such circumstances in the past fortnight.Luena's murder was confirmed by regional police commander Ulrich Matei, who said the motive was unknown and the killers were being sought.At a press conference in the economic capital Dar es Salaam, Chadema deputy secretary John Mnyika said Luena had left his home on Thursday night to look into a power cut affecting his house alone."He was then attacked by a group of men armed with machetes," Mnyika said."This is a political assassination," Mnyika added, saying Luena had been defending residents against alleged land-grabbing by local ruling party officials.KEEP UPDATED on the latest news from around the continent by subscribing to our FREE newsletter, Hello Africa.FOLLOW News24 Africa on Twitter and Facebook. Mnyika said the killing was part of an assault on the opposition "from all sides by the government of President (John) Magufuli and the police.""The time for self-defence has come!" he added.On February 13, Daniel John, responsible for the Chadema party in the Hananasif district of Dar es Salaam, was found dead with machete wounds to the head during a heated local election campaign.Chadema president Freeman Mbowe blamed youth members of the ruling Chama Cha Mapinduzi (CCM).In September 2017, senior opposition lawmaker Tundu Lissu was shot several times at his home in the capital Dodoma. He was rushed to the Kenyan capital Nairobi where he was in intensive care for several months, before being transferred to a hospital in Brussels.Chadema accuses the ruling party of being behind that attack, claims rejected by the government.