President Yahya Jammeh has told the BBC that he will rule for "one billion years", if God wills.
He said critics who accused him of winning last month's elections through intimidation and fraud could "go to hell".
The West African regional body Ecowas said the electorate had been "cowed by repression".
Mr Jammeh, who took power in a coup in 1994, was re-elected with 72% of the figures, official figures show.
The 46 year old said he did not fear a fate similar to Egypt's ousted President Hosni Mubarak or killed Libyan leader Muammar Gaddafi.
"My fate is in the hands of almighty Allah," he told the BBC's Focus on Africa programme.
Journalist's death
"I will deliver to the Gambian people and if I have to rule this for one billion years, I will, if Allah says so."
The November poll was the fourth since Mr Jammeh overthrew 's first post-independence leader Dawda Jawara aged just 29.
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I will not bow down before anybody, except the almighty Allah and if they [human rights groups] don't like that can go to hell”
Yahya Jammeh
The Gambia's president
Opposition candidates Ousainou Darboe and Hamat Bah took 17% and 11% respectively.
Mr Darboe called the results "bogus, fraudulent and preposterous".
The Economic Community of West African States (Ecowas) refused to send observers, saying the polls would not be free and fair because voters and the opposition had been "cowed by repression and intimidation".
The media group Reporters Without Borders (RSF) says there is "absolute intolerance of any form of criticism" in The Gambia, with death threats, surveillance and arbitrary night-time arrests the daily lot of journalists "who do not sing the government's praises".
In 2004, the editor of the privately owned The Point newspaper, Deyda Hydara, was gunned down, but no-one has been charged over his murder.
In the BBC interview, Mr Jammeh denied that the government's security agents had killed him.
President Yahya Jammeh Overthrew The Gambia's first president as a 29-year-old army lieutenant in 1994.Previously won three widely criticised elections
Accused of not tolerating opposition or independent journalists
Claimed in 2007 that he could cure Aids with a herbal concoction
Warned in 2008 that gay people would be beheaded
Eight men sentenced to death last year after being accused of plotting to overthrow him
When asked about Dayda Hydara's death, he said.
"Listen to me: Is he the only Gambian who died? Is he better than Gambians who die in accidents, Gambians who die at sea, Gambians who die on their way to Europe?" Mr Jammeh asked.
"Other people have also died in this country. So why is Deyda Hydara so special?"
Mr Jammeh said he was not bothered by the criticism of human rights groups.
"I will not bow down before anybody, except the almighty Allah and if they don't like that they can go to hell," he said.
In 2007, Mr Jammeh caused controversy by claiming that he could cure Aids with a herbal concoction.
Later, he also claimed that he could cure infertility among women.
Medical groups denounced him for making such claims.
The tiny West African state is a popular tourist destination.
