Liberia is facing a “serious threat” to its national existence as the deadly Ebola virus “spreads like wildfire” there, its defence minister says.

Brownie Samukai told the UN Security Council that the international response to the crisis was “less than robust”.

The World Health Organization (WHO) has warned that thousands more cases could occur in Liberia, which has been worst hit by the West Africa outbreak.

Some 2,288 people have died from Ebola in Liberia, Guinea and Sierra Leone.

The WHO says half of these deaths occurred in the three weeks running up to 6 September.

In Nigeria, eight people have died out of a total 21 cases, while one case has been confirmed in Senegal, with no deaths.

Liberia’s defence minister warned on Tuesday that the country’s weak health system was already overwhelmed by the number of cases.

Mr Samukai told UN Security Council members that Liberia lacked “infrastructure, logistical capacity, professional expertise and financial resources to effectively address this disease”.

“The deadly Ebola virus has caused a disruption of the normal functioning of our state,” he said.

Separately on Tuesday, the UN’s envoy in Liberia said that at least 160 Liberian health workers had contracted the disease and half of them had died.

Karin Landgren described the outbreak as a “latter-day plague” that was growing exponentially.

She added that health workers were operating without proper protective equipment, training or pay, in comments to the UN Security Council.

“Liberians are facing their gravest threat since their war,” Ms Landgren said.

“I don’t think anybody can say right now that the international response to the Ebola outbreak is sufficient,” US ambassador to the UN Samantha Power said after the Security Council briefing.

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

Unlike other West African nations affected by the outbreak, efforts to contain the virus in Liberia were not working well, the WHO has said.

The reason for this remains unclear; however, experts say it could be linked to burial practices, which can include touching the body and eating a meal near it.