Zambian authorities arrested opposition party members Tuesday, a day after the killing of a ruling Patriotic Front (PF) activist and ahead of by-elections this week, dpa reported. Opposition groups have charged that the government is cracking down on them ahead of the polls for vacancies in parliament and local municipalities on Thursday. The PF youth activist was allegedly killed by members of opposition group the United Party for National Development, led by Hakainde Hichilema, who was among those arrested. The Electoral Commission of Zambia this week overruled a police ban on political rallies which had largely been focused on opposition groups.