The United States has announced sanctions on Zimbabwe's State Security minister and the southern African country's envoy to Tanzania for their roles in the killings and abductions of protesters.

Washington accused State Security minister Owen Ncube, an ally of President Emmerson Mnangagwa, of masterminding the abductions and torture of government critics in last year’s protests.

Zimbabwe's Ambassador to Tanzania Anselem Sanyatwe, a former commander of the presidential guard, was sanctioned for allegedly deploying soldiers who killed six protesters a few days after the 2018 elections.

“These actions follow Sanyatwe and Ncube's designations for gross violations of human rights by the State Department in September and October 2019, which blocked Ncube and Sanyatwe from entering the United States,” the State Department said in a statement on Wednesday.

The US announced a travel ban and asset freeze on them; and its citizens are prohibited from engaging in business deals with them.

The US also removed from the list former government minister Ray Kaukonde and three other officials, Shuvai Makova, Sithokozile Mathuthu and Naison Ndlovu, who have since died.

Zimbabwe, however, protested against the latest move by the US, saying it derailed efforts to revive relations between the two countries.

“The decision can only further erode trust and confidence in the relationship between Zimbabwe and the United States at a time when, more than ever, confidence building measures are required so as to sustain the ongoing process of re-engagement,” said Foreign Affairs Minister Sibusiso Moyo.

Dr Moyo said the sanctions are unfair.

“In taking the action, the US government appears unilaterally to have charged, tried, convicted and sentenced two very senior Zimbabwean nationals…the very antithesis of justice as we understand it,” he added.

Talks between Zimbabwe and the US to restore relations have stalled because Washington is not happy with Harare' s pace in implementing reforms.

Last week Washington renewed its sanctions against Zimbabwe for another year, citing alleged human rights violations by security forces.

President Donald Trump’s administration accused President Mnangagwa of squandering an opportunity to reform after a military coup that toppled long-time ruler Robert Mugabe in 2017

The European Union, Australia, Canada and New Zealand have maintained sanctions against Zimbabwe for close to two decades over human rights violations and electoral fraud.