Zimbabwe's main opposition party will make a statement on Tuesday about its plans to challenge the country's election results in the courts, though it believes the judicial system is biased against it, a party spokesperson said.Nkululeko Sibanda, an official in the Movement for Democratic Change party, also charged on Monday that security forces are acting with a "sense of impunity" in alleged raids on the homes of opposition supporters.Some MDC members are in hiding and "a large number" are "unaccounted for," Sibanda said. He did not say exactly how many people might be missing, and could not confirm whether they were in custody or had temporarily left their homes to hide.The Zimbabwe Electoral Commission says President Emmerson Mnangagwa and the ruling Zanu-PF party won the July 30 election. The opposition says the results are fraudulent. International election observers have urged any aggrieved Zimbabweans to take election complaints to the courts.A total of 27 opposition activists who were arrested for allegedly inciting violence appeared in court on Monday. They include three who were arrested over the weekend, said Zimbabwe Lawyers for Human Rights.Most of the activists were detained last week at the opposition party's headquarters where "they had gone to surrender some election return materials and where they were waiting to receive their transport and food allowances after serving as election agents," the lawyers' group said.The arrests followed a military crackdown in downtown Harare after protesters, some throwing rocks and damaging property, took to the streets to allege that the election was rigged. Soldiers opened fire, and six people, including bystanders, were killed.In an interview with Sky News, Mnangagwa said politics should take a "backseat" and that the country must unite to build its shattered economy."Those who voted against me, those who vote for me, we say Zimbabwe is ours together. Let's move on," said Mnangagwa, an ex-vice president who took over from Robert Mugabe. The former longtime leader resigned after a military takeover in November.* To follow the latest on the Zimbabwe elections SIGN UP TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.