The Ukrainian Navy is now saying that two of its ships have been seized and two of its servicemen wounded.
If you speak the language, you might also want to follow a live blog of the current escalation in the Sea of Azov that has been started by RFE/RL's Ukrainian Service.
More off-the-cuff analysis
Indeed...
More worrying developments
Another disquieting development: Ukrainian President Petro Poroshenko has reportedly convened his war cabinet.