NAIROBI, Oct 7, 2008 (AFP) - The American author of a best-selling, controversial book blasting White House hopeful Barack Obama was detained Tuesday by security officials in Kenya, police said.

Jerome Corsi 'has been detained and he is currently being held at the immigration office' in Nairobi, a top police official told AFP on condition of anonymity.

Corsi was to unveil 'The Obama Nation' to the Kenyan public at a Nairobi hotel.

Obama's father, now deceased, was Kenyan and the US senator running for president enjoys wide support in East Africa.

In a press release distributed earlier this week, Corsi announced he would 'expose deep secret ties between between US Democratic presidential candidate Sen. Barack Obama and a section of the Kenyan government leaders.'

He was also to detail Kenyan leaders' 'connections to certain sectoral groups in Kenya and a subsequent plot to be executed in Kenya should Sen. Obama win the American preisdency,' the release said.

The police official denied Corsi's detention was linked to the contents of his book.

'Just like anybody else, we are concerned with his immigration papers. We have nothing to do with the book or whoever it's about. It's about the law of Kenya,' he said.

Corsi made his name by co-authoring 'Unfit for Command,' which maligned 2004 Democratic presidential nominee John Kerry's Vietnam War record and is believed to have contributed to his defeat by President George W. Bush.

Corsi's book on Obama, subtitled 'Leftist Politics and the Cult of Personality,' was released on August 1.

The book's publisher, Threshold Editions, said it examined 'why the extreme leftism of an Obama presidency would leave the United States weakened, diminished and divided, why Obama must be defeated -- and how he can be.'