The EU already imposed sanctions on Russia in March over its stealth invasion and annexation of Crimea, but those lacked teeth. More sanctions are ready, but some EU members are displaying a strong reluctance to punish the Kremlin further unless the Russian overtly invade Ukraine.
This map from Reuters shows the basic breakdown:
REUTERS
WSJ notes that tough sanctions could include banning arms exports, prohibiting purchases of Russian fertilizer, and curbing imports of Russian gas. The U.S. is urging Ukraine to intensify the sanctions, but there seem to be a lot of political factors at play.
Here's a map detailing the EU's reliance on Russian gas. Interestingly, several countries that import a significant amount of Russian gas are pro-sanctions while others that do not import any Russian gas are still against sanctions.
REUTERS
Map of Europe showing how heavily EU countries rely on Russian gas imports.
As tensions continue to simmer in eastern and southern Ukraine as pro-Russian gunman - some of whom are suspected of being Russian special forces - the political resolve of relucant EU members will be an key storyline to watch.