Former Kenyan government minister Raila Odinga has told the police he believes his life is in danger.
Raila Odinga intends to run for president in 2007
Mr Odinga, who was sacked last month, says he has received assassination threats and is constantly being pursued by men in unmarked vehicles.
Mr Odinga is leader of the Orange Democratic Movement which campaigned against the constitutional proposals backed by President Mwai Kibaki.
He was angry that a new promised role of prime minister was watered down.
A majority of Kenyans - including several cabinet ministers - voted against the changes in a referendum in November.
Deputy Security Minister Mirugi Kariuki accused Mr Odinga of seeking publicity.
He said that the police would nevertheless take his allegations seriously.
Government spokesman Alfred Mutua rejected the claim.
"We are not in the business of following people for political reasons," he said.