Here's what you need to know about the Ukraine crisis right now:
HEADLINES
* President Vladimir Putin put Russia's nuclear deterrent on high alert on Sunday in the face of a barrage of Western reprisals for his war on Ukraine, which said it had repelled Russian ground forces attacking its biggest cities.
* Blasts were heard in the capital of Kyiv and in the major city of Kharkiv on Monday morning, Ukrainian officials said, while a residential building in the city of Chernihiv in northern Ukraine was on fire after being struck by a missile.
Read More
Sign Up for Lisa's Top Ten to get a daily briefing on the world each morning.
Start your free trial today.