President Emmerson Mnangagwa. [AP photo]

Zimbabwe's president on Friday officially opened a ruling party congress that is set to renominate him as the party's presidential candidate for next year's election, but soaring inflation and a government crackdown on dissent are fueling tensions in the southern African nation.

The ruling ZANU-PF party on Saturday will officially nominate President Emmerson Mnangagwa as its election candidate and party leader for the next 5 years, a choreographed step that all party organs have already endorsed him.

Yet the 80-year-old is likely to face a strong challenge from 44-year-old popular opposition leader, Nelson Chamisa, whom he narrowly beat in 2018.

Mnangagwa took over from his mentor, the late Robert Mugabe, following a coup in 2017 and subsequently won a disputed election the following year.

"Let us give him another five years...so that he propels our country to the land of our dreams. He is the one and only candidate we know," vice president and former army general Constantino Chiwenga said to applause from hundreds of party supporters in the capital, Harare, many dressed in the party's green, yellow and red colors emblazoned with the president's face.

In turn, Mnangagwa promised a "thunderous victory."

"We pronounce our readiness to yet again win another mandate to govern. Under our watch, ZANU-PF will continue to govern this land," he said.

Zimbabwe's electoral body says the general election should be held by August next year. But many opposition figures say they are already battling intense government repression similar to that during Mugabe's iron-fisted rule.

Dozens of people - including opposition supporters, political activists, journalists, church leaders, trade unionists and student leaders - have been arrested, detained or are appearing in court on charges that some legal experts equate to harassment.

Criticism of Mnangagwa's government has been stoked by Zimbabwe's inflation of 268%, currently estimated to be one of the world's highest. Rising numbers of people are being pushed into informal trade such as street vending.

Mnangagwa blames sanctions imposed by the United States about two decades ago for his country's economic problems.

In a tweet on Oct. 25, an annual date that Zimbabwe and the regional Southern African Development Community body have set to lobby against the sanctions, the U.S. Embassy in Harare said "the direct impact of sanctions on the average Zimbabwean is minimal compared to the economic devastation caused by years of corruption, poor policy choices, and economic mismanagement."