Tanzania's main opposition party, CHADEMA, has been disqualified from the upcoming elections, a senior election official confirmed on Saturday.

Ramadhani Kailima, director of the Independent National Elections Commission, stated that the party failed to sign a necessary code of conduct document by the deadline, invalidating its participation in the presidential and parliamentary elections set for October.

“Any party that did not sign the code of conduct will not participate in the general election,” said Ramadhani Kailima, the commission’s director of elections, adding that the disqualification extends to all by-elections until 2030.

This follows recent treason charges against CHADEMA’s leader, accused of attempting to disrupt the vote. Hassan's party, Chama cha Mapinduzi (CCM), has consistently claimed that the government upholds human rights and rejects accusations of human rights abuses.

CHADEMA, on the other hand, has not yet responded to the election commission's decision. Earlier, the party announced it would boycott the election code of conduct signing ceremony, continuing its demand for reforms.

Meanwhile, prosecutors have charged CHADEMA leader Tundu Lissu with treason, accusing him of inciting rebellion to prevent the election from taking place. Lissu, facing the death penalty, was not allowed to plead to the charge.

CHADEMA had previously warned of a possible election boycott unless key reforms were implemented to address what it describes as a biased electoral system favoring the ruling party.

He was arrested after gracing a public rally in which he called for electoral reforms ahead of planned general elections in October. Lissu, chairperson of the main opposition party CHADEMA, was arrested on Wednesday night over what regional police called incitement.

The opposition in Tanzania has been calling for electoral reforms to ensure the upcoming poll is free and fair. Lissu on Thursday afternoon arrived at the Kisutu magistrate's court in the commercial capital Dar es Salaam appearing in high spirits and in the company of his lawyers and opposition party politicians.

The opposition leader was forced into a police vehicle late Wednesday after he had just finished addressing a public rally in Mbinga, south of the country more than 1,000 kilometers (600 miles) from Dar es Salaam.

“I came here, we held a peaceful meeting, and now I understand the tactics of the police. We are now clear on the situation; I will not enter the vehicle. There is no need for that. We will sleep here. What is the problem?” Lissu asked the police, moments before his supporters were teargassed.

Human rights activists have accused the government of President Samia Suluhu Hassan of heavy-handed tactics against the opposition.

The government denies the claims. In 2017, three years before the last election, Lissu survived an assassination attempt after being shot 16 times.

Tanzania is set to elect the president and members of parliament in the October elections.

HADEMA has been critical of the absence of an independent electoral commission and laws that favor the ruling party, CCM, which has been in power since Tanzania’s independence in 1961.