Liberian President Ellen Johnson Sirleaf has sacked 10 government officials who have been "out of the country without an excuse," amid a national Ebola crisis.

She said the officials had shown "insensitivity to our national tragedy and disregard for authority".

The 10 were given a one-week ultimatum more than a month ago to return home.

Sierra Leone, Liberia and Guinea are the worst-hit countries in an outbreak that has killed more than 2,400.

The 10 officials include two commissioners, six assistant ministers and two deputy ministers at the justice ministry.

The BBC's Jonathan Paye-Layleh says a press release issued from the presidency on Saturday reported that the officials had been fired "with immediate effect".

The press release went on: "Junior officials who are not subject to presidential approval will forfeit all compensation and benefits until they return home to join in the fight against the Ebola virus disease."

It listed the names of eight people in the category.

President Johnson Sirleaf has appealed directly to US President Barack Obama for urgent help in tackling the outbreak.

In a letter dated 9 September she asks Mr Obama to build and operate at least one Ebola treatment centre in the capital, Monrovia.

"Without more direct help from your government, we will lose this battle against Ebola," she writes.

The World Health Organization (WHO) warned recently that thousands more cases could occur in Liberia.

Ebola spreads between humans by direct contact with infected blood, bodily fluids or organs, or indirectly through contact with contaminated environments.