Robert Mugabe, the president of Zimbabwe, celebrated his 93rd birthday on Tuesday by pledging to remain in power despite growing signs of frailty, and endorsing Donald Trump’s brand of American nationalism.

“When it comes to Donald Trump, on the one hand talking of American nationalism … America for Americans … on that we agree: Zimbabwe for Zimbabweans,” said Mugabe, who took power in the former British colony in 1980.

In a rambling interview with state-owned TV, Mugabe said he hoped Trump, the US president, might review the sanctions imposed on him and members of his inner circle in 2003 over alleged human rights violations and vote rigging. The sanctions were extended by the Obama administration.

Zimbabwean media loyal to the government made no secret of their delight in Trump’s shock presidential election victory in November. In this week’s interview, Mugabe said he had not wanted Hillary Clinton to claim the White House.

“We are just now under sanctions imposed not by Donald Trump, but by Obama. What arrogance is that?” Mugabe said.

Critics accuse Mugabe of wrecking one of Africa’s most promising economies through policies such as the violent seizure of commercial farms owned by white people, and money printing. He is also accused of holding on to power through rigged elections and the ruthless repression of dissent.

He and his Zanu-PF party say the economy has been undermined by western powers.

Several incidents in recent years have highlighted Mugabe’s age, including a public fall at Harare airport in 2015. In September of that year he read a speech to parliament apparently unaware that he had delivered the same address a month earlier.

During the birthday interview, he appeared to grow increasingly tired, pausing at length between sentences and speaking with his eyes barely open.

Mugabe, who has ridiculed regular reports that he is close to death, spoke about creating jobs in Zimbabwe’s wrecked economy, the country’s extreme cash shortage, and his controversial wife, Grace.

Robert Mugabe with his wife Grace at his 92nd birthday celebrations last year. Photograph: Tsvangirayi Mukwazhi/AP

Mugabe described his 51-year-old spouse, who some observers believe is being groomed as a successor, as “a very strong character” and said she was “very much accepted by the people”.

Grace Mugabe,who has a reputation for extravagance and fierce verbal attacks on rivals, was appointed head of Zanu-PF women’s wing in 2014 in a surprise move that leaves her well-positioned to succeed her husband.

Another leading candidate is Mugabe’s vice president, Emmerson Mnangagwa. Earlier this year Mnangagwa posted a picture of himself with a mug bearing the slogan “I’m the Boss”, prompting speculation that he was preparing a bid to oust the president.

In this week’s interview, Mugabe gave no indication that he plans to hand over the reins. Some observers have suggested that his comments signal thathe is being pressured by younger aides to remain in charge, despite his evident fatigue and recurrent illnesses.

“The call to step down must come from my party,” Mugabe said. “In such circumstances I will step down.

“They want me to stand for elections … If I feel that I can’t do it any more, I will say so to my party so that they relieve me. But for now, I think I can’t say so. The majority of the people feel that there is no replacement – a successor who to them is acceptable.”

A spokesman for the opposition Movement for Democratic Change marked Mugabe’s birthday with a stinging opinion piece in the privatelyowned NewsDay paper.

“Today’s problems need today’s people. Yet you do not even belong to yesterday’s generation. At 93, you certainly belong to yesterday but one,” wrote Luke Tamborinyoka.

The state-owned Herald newspaper, on the other hand, carried a 24-page birthday supplement, packed with goodwill messages from government departments.

A bigger celebration is set for Saturday in Matopos, 500km (350 miles) southwest of Harare, where thousands of Zanu-PF officials and supporters are expected to gather.

Large game animals are often slaughtered for the occasion. In previous years Mugabe has reportedly been offered elephants, buffalo and impala for the feast.