than 3,400 people.

Following Mr Duncan's death, US Secretary of State John Kerry made an urgent appeal for nations to "step up" their response to the virus and said more money, equipment and personnel were needed in the fight, the Huffington Post reported.

He added that while progress in combating the disease was being bade, it was far too slow.

Speaking with British Foreign Secretary Philip Hammond, Kerry said it is essential for airlines to keep flying to west Africa and for borders to remain open to allow for the movement of assistance and medical staff.

Officials in Dallas are now working to keep the virus contained, and around 48 people with whom Duncan had been in contact are being monitored.

The four people living in the northeast Dallas apartment where Duncan stayedUkraine and Shell sign '$10bn' shale gas deal Published duration 24 January 2013

image copyright Reuters image caption Ukrainian President Viktor Yanukovych described the deal as "a great event"

Ukraine has signed a major shale gas deal with Royal Dutch Shell - a move seen as an attempt by Kiev to reduce its dependency on Russian gas imports.

The contract - reportedly worth $10bn (£6bn) - was agreed on the sidelines of the World Economic Forum in the Swiss ski resort of Davos.

Ukraine is believed to have some of the largest shale gas reserves in Europe.

New technology means they are more easily recoverable, but opponents warn of a high risk of pollution.

The deal between Ukraine's state company Nadra Yuzivska and Shell was signed by the energy giant's CEO Peter Voser and