The first person to be diagnosed with Ebola within the US has died, Texas hospital officials have said.
Thomas Eric Duncan, 42, who caught the virus in his native Liberia, was being treated with experimental drugs in isolation in a Dallas hospital.
Earlier the US announced new screening measures at entry points to check travellers for symptoms of the virus.
It has killed 3,865 people, mostly in Liberia, Sierra Leone and Guinea, in the worst Ebola outbreak yet.
“It is with profound sadness and heartfelt disappointment that we must inform you of the death of Thomas Eric Duncan this morning at 7:51 am,” a spokesman said in a statement.
The news came shortly after US Secretary of State John Kerry urged all nations to boost their response to combat the virus.
“More countries can and must step up,” he said in a joint press conference with his British counterpart Philip Hammond.
The US has pledged as many as 4,000 troops to the region, while the UK is sending 750 military personnel to Sierra Leone.
Duncan, who worked as a driver for a courier company, tested positive in Dallas, Texas, on 30 September, 10 days after arriving on a flight from Monrovia via Brussels.
He become ill a few days after arriving in the US but even after going to hospital and telling medical staff he had been in Liberia he was sent home with antibiotics.
Four days later, he was placed in isolation but his condition continued to worsen and this week he was given an experimental drug.
Ten people with whom he came into contact are being monitored for symptoms.
Following Duncan’s diagnosis, the first case of contagion outside of Africa was confirmed in Spain, where a nurse who treated an Ebola victim in Madrid contracted the virus herself.