“Unidentified gunmen” — a.k.a. Russian soldiers — surrounded the Ukrainian military base at the Perevalne village in Crimea on Sunday morning. Ukraine troops are refusing to stand down.

Journalists on scene are sharing background and photos of the tense scene.

Civilians from both sides are also there.

Previous:

‘The text does not limit it to Crimea’: Putin reportedly asks parliament to use military in all of Ukraine; Update: Parliament approves

‘This isn’t parody?’ Russia occupies Crimea, MSNBC spots race squirrel [pic]

Unidentified gunmen take control of airport in Crimea’s capital [photos]