A senior British minister ruled out sending arms to Ukraine as the United States and European nations sought ways to pressure Russia over the conflict in Ukraine's east.

William Hague, who was UK foreign secretary until last year, said governments should think "very, very carefully" about such a move.

"We are not planning, as the UK, to send arms to Ukraine. It has not been our approach in any of the conflicts in recent years to send arms into those conflicts," Hague told BBC television.

Britain is already sending non-lethal equipment such as light armored personnel carriers to Ukraine.

Foreign Secretary Philip Hammond said earlier this month that, while Britain was not currently planning to supply "lethal aid" to Ukraine, "we reserve the right to keep this position under review".