Cameron warns Putin of tough response from West

David Cameron has told the BBC that Russia will face a tough response from the West unless it stops sending troops and tanks to support separatist rebels in Ukraine.

Speaking at the start of the G20 summit in Brisbane, Mr Cameron said Moscow should stick to the terms of a ceasefire agreement.

The summit normally focuses on economic issues but the agenda is likely to be overshadowed by the West's increasingly difficult relationship with the Kremlin.