Prime Minister David Cameron said he gave Russian president Vladimir Putin a "very clear and firm set of messages" during face-to-face talks in Paris about the Ukraine crisis and said the current situation is "not acceptable".
Barack Obama has told his Russian counterpart Vladimir Putin that he must recognise the new Ukrainian President, Petro Poroshenko in order to help de-escalate the crisis in eastern Ukraine.
According to a White House official, the US President also told Mr Putin that if Russia works with the new Ukrainian authorities there could be "openings" to reduce tensions in the region.
Deputy national security adviser Ben Rhodes added that Mr Obama had demanded "ceasing support for separatists in eastern Ukraine, and stopping the provision of arms and material across the border".
The experts suggest smoking “stigma” has inadvertently diverted research attention away from lung cancer.
Theresa May is facing calls for a full police inquiry after the leak of secret discussions by the UK’s top national security body.
Gusts of up to 75mph will hit the south-west coast of the UK.