Russian and Ukrainian Troops in Tense Crimea Standoff

Russian and Ukrainian troops were involved in a standoff at a Crimea airbase early on Tuesday morning, marking one of the tensest moments of the Ukrainian crisis so far.

Russian troops took control of the Belbek air base in the Crimea region, the peninsula that Russia now effectively controls, firing warning shots into the air as some 300 unarmed Ukrainian soldiers who were previously stationed in the airfield demanded their jobs back early on Tuesday morning.

TIME’s Simon Shuster tweeted from the airbase as the situation unfolded—the shots are believed to be the first fired since the crisis in Crimea began.

The latest reports suggest the standoff is continuing, as the unarmed Ukrainian troops have demanded to guard the airbase jointly with the Russians. Tensions are running high in the region as an estimated 16,000 Russian troops—whom Russian President Vladimir Putin has now ordered to return to their bases—tightened their effective control over the Black Sea peninsula over the weekend. Putin denied on Tuesday that the men guarding military bases in Crimea were Russian soldiers, despite their military uniforms that resemble Russian military outfits.