The United Nations has spoken out against what it said was an intensifying crackdown on the opposition and media in Uganda ahead of next month’s election.

Its rights agency said credible reports indicated that at least 550 people have been arrested and detained since the start of the year.

This included members and supporters of presidential candidate Bobi Wine’s main opposition National Unity Platform (NUP) party.

“We deplore the intensifying crackdown on the opposition and media in Uganda ahead of next month’s general election,” said Ravina Shamdasan, spokesperson for the UN High Commissioner for Human Rights (OHCHR).

“It is deeply regrettable that election campaigns have once again been marked by widespread arbitrary arrests, detentions, and the use of unnecessary or disproportionate force against the opposition, as well as undue restriction of press freedom,” she said.

Reports of arrests and detentions, as well as enforced disappearance, torture and other ill treatment of opposition supporters and activists have been on a steady increase over the past year.

The OHCHR said security forces have been accused of using unmarked minibuses widely known as “drones” to transport people to unofficial places of detention known as “safe houses” where they are held incommunicado.

It added that heavily armed security forces have been deployed at locations where the NUP was due to hold rallies.

The OHCHR said it urged the authorities in Uganda to end the pattern of repression and cease the use of “such repressive tactics”.

It called on the authorities to impartially investigate allegations of enforced disappearance, arbitrary arrest and detention, and torture, and punish those responsible.

The agency said all detained individuals should be released and Ugandans must be allowed to “fully and peacefully exercise their right to participate” in their country’s public affairs.

Wednesday’s statement also decried restrictions of press freedoms, highlighting recent cases where journalists had their accreditation withdrawn apparently due to critical reporting.

Eighty-one-year-old President Yoweri Museveni is seeking to extend his 40-year-rule in the 15 January polls.