Talks over a gas pricing dispute between Ukraine and Russia have ended without an agreement, according to a source close to the negotiations.
The Ukrainian government has a deadline of 10.00 GMT tomorrow to pay its $1.95 billion debt.
It is possible that the Kremlin could now opt to cut off the gas supply to Ukraine, potentially causing difficulty for other European countries that receive their gas via Ukraine.
More top news
Sunshine and showers for tomorrow
Addressing veterans at an American Legion conference in Reno, Nevada, the president spoke in measured tones and stuck to prepared remarks.
Uncertainty over Brexit in the UK and strong economic data from Europe both contributed to the slump in the British currency.