Russian President Vladimir Putin saidhe supported in principle Washington's proposal for a 30-day ceasefire with Ukraine but that his forces would fight on until several crucial conditions were worked out.

The barrage comes less than 24 hours after Russian President Vladimir Putin discussed details of the U.S. proposal for a 30-day ceasefire with a U.S. envoy.

The last time Ukraine signed a peace accord with Russia, 10 years ago, it brought only sporadic violence, mounting distrust, and eventually full-scale war. Here’s what we can learn from that history.