Tanzanian opposition lawmaker Zitto Kabwe was arrested in Dar es Salaam on Wednesday after having claimed that dozens of people were killed in recent clashes between herders and the security forces, his ACT party said.Kabwe, head of the Alliance for Change and Transparency and its only member of parliament, is an outspoken critic of President John Magufuli."Our leader was arrested at his home. He is now being questioned by police. Our lawyers are with him," ACT spokesperson Ado Shaibu said."We do not yet know exactly why he was arrested, but according to initial police explanations it has to do with our press conference on Sunday," the spokesperson added.At that briefing in Dar es Salaam, Kabwe said about 100 people were killed in clashes between police and herders some 10 days earlier in the western Kigoma province, where he is from.Police put the figure at two policemen and two herders killed, and said the herders had unlawfully taken their cattle into a protected reserve.Kigoma police chief Martin Ottieno challenged Kabwe to show for his claim.On Wednesday, police commander Jumanne Muliro of Kinondoni, where Kabwe was being questioned, told the independent daily Mwananchi: "We will provide more information later on" about his arrest.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.