Sierra Leone's vice president, Samuel Sam-Sumana, has requested asylum at the US embassy in Freetown after soldiers surrounded his home, following his expulsion from the ruling All People's Congress (APC) party this month.

Sumana was expelled from President Ernest Bai Koroma's APC party after an investigation accused him of creating his own rival political movement, leaving doubt over whether he could continue as vice president.

"I have fled my house and am with my wife in a place I cannot disclose, waiting to hear from the US ambassador, whom I have asked for asylum," Sam-Sumana told the Reuters news agency on Saturday.

A source at the US embassy, who did not wish to be named, told Reuters that Sam-Sumana had entered the building. but it was not immediately possible to confirm that officially.

Government spokesman Abdulai Bayraytay, who said he was travelling with Bai Koroma in northern Sierra Leone, declined to comment.

In late February, Sam-Sumana said that he was placing himself in a 21-day quarantine after one of his bodyguards died of Ebola amid a surge in new infections in the West African country.