On his 93rd birthday, the world's oldest head of state, Robert Mugabe, insisted he has no plans to stand down as Zimbabwe's leader and vowed to stand again in the country's 2018 election.

Speaking in an interview with state-run media, the controversial leader also said he admires Donald Trump's "America First" policy, but condemned the US President's plans for a wall on the country's border with Mexico as "quite nasty".

President Mugabe said President Trump's "America First policy" resonates with his own thinking: "When it comes to Donald Trump, on the one hand talking of American nationalism, well, America for America, America for Americans - on that we agree. Zimbabwe for Zimbabweans."

The Zanu-PF leader also said he hoped President Trump's administration would remove sanctions placed on Zimbabwe more than a decade ago over alleged human rights abuses and electoral irregularities.

However, President Mugabe did question President Trump's plan to build a wall on the Mexican border: "It appears quite nasty. I don't know how the Mexicans will take it. I thought the Americans once loved Mexico.

"I don't know. Give him time. He might come up with better policies."

President Mugabe has previously defended the Republican, saying he did not want Hillary Clinton to win the election.

In the interview the 93-year-old described his 51-year-old wife, Grace, an increasingly political figure, as "fireworks" due to her feisty remarks in his defence.

Ms Mugabe has frequently defended her husband against critics who say it is time for him to step down, and in an interview earlier in February she said her husband could run "as a corpse" in the election of he dies before the vote.

Speaking at a rally the First Lady urged supporters to put her husband's name on the ballot to show their love for him in the event of the 93-year-old's health failing him in the next few months.

Grace Mugabe told the cheering crowd: "If God decides to take him, then we would rather field him as a corpse."

Ms Mugabe's political rise is a source of worry for opposition figures and some officials in the ruling Zanu-PF party who suspect she is positioning herself for a more powerful role in government.

President Mugabe has described his wife as "very much appreciated by the people" and a "very strong character", and said the women's wing of the ruling party has chosen his wife as its head because of her political ambitions.

A large birthday celebration for President Mugabe is scheduled to take place on Saturday.

For his 92nd birthday Mr Mugabe threw a lavish £800,000 party as the country was hit by drought and more than a quarter of the population required food aid.

Mr Mugabe has been president of Zimbabwe since 1987, previously serving as prime minister of the country since 1980, when white minority rule ended.

The controversial leader has also brushed aside persistent allegations of corruption against senior officials, saying rumour-mongers were merely targeting "big fish" in his administration.

In Tuesday's interview Mr Mugabe said he would act if shown evidence of corruption - even though graft scandals involving ministers and even members of his own family are regular fare in local newspapers.

The country's anti-corruption commission is currently fighting the higher education minister and his deputy, who are accused of embezzling hundreds of thousands of dollars from a state fund. They deny the charges.

In Zimbabwe investigations are rare and arrests even rarer, yet the country loses around £800 million annually to corruption, with police and local government officials among the worst offenders.

Zimbabwe's state-owned Herald newspaper carried a 24-page birthday supplement, packed with goodwill messages from government departments to Mr Mugabe.

President Mugabe has previously declared he wants to live until he is 100 and rule for life.