Simon Tisdall: Why Putin is dictating terms to Kerry on Ukraine
Earlier Russian President Vladimir Putin has warned that Russian gas supplies to Europe could be disrupted if Moscow cuts the flow to Ukraine over unpaid bills.
High-level talks to defuse the Ukraine crisis, due to be held by the U.S., Russia, the EU and the Kyiv government next week, amount to a big personal test for John Kerry after a notably accident-prone first year as U.S. President Barack Obama's secretary of state.
