Seventeen suspected Ebola patients are "missing" in Liberia after a health centre in the capital was attacked, the government says.

时事英语新闻：利比里亚17名埃博拉患者失踪

利比里亚政府称，首都一家卫生站遭到攻击，17名埃博拉病毒疑似患者“失踪”。

The government had previously denied they were missing, saying all patients had been moved to another facility.

The Ebola outbreak, which has spread from Guinea to Liberia, Sierra Leone and Nigeria, has killed at least 1,145.

The World Health Organization (WHO) has called for exit screenings on all travellers from affected countries.

It wants checks at airports, sea ports and major land crossings.

Several airlines have already stopped flying to Guinea, Liberia and Sierra Leone.

Cameroon has closed its land, sea and air borders with Nigeria, reports say.

The Ebola outbreak in West Africa is the world's deadliest to date. The disease has no known cure.

Meanwhile, the UN's chief co-ordinator in Sierra Leone, David McLachlan-Karr, told the BBC that Ebola had spread to 12 out of 13 of the country's districts.

"While Sierra Leone was the last affected of the three Mano River countries [Guinea, Liberia and Sierra Leone] to have confirmed [cases] of Ebola, now it's the country with the most cases," he said.

There have been at least 810 cases of Ebola reported in Sierra Leone, including 348 deaths, according to WHO figures.

时事英语新闻：Meanwhile, the UN's chief co-ordinator in Sierra Leone, David McLachlan-Karr, told the BBC that Ebola had spread to 12 out of 13 of the country's districts.