Ukraine Crisis: Militants, Army Face Off in East Amid Soaring Tensions

Helicopters and a fighter jet circled the skies above the tense eastern Ukrainian city of Kramatorsk on Wednesday, while on the streets below a column of tanks rolled through the city - one with a Russian flag affixed.

A convoy of armored personnel carriers also entered the city of Slaviansk, some carrying Russian or regional separatist flags.

Events are moving fast in Ukraine's restive Donetsk region, and confusion is rife.

According to one state-run Russian news agency, residents of Kramatorsk captured several armored vehicles from the Ukrainian army, while another said the crew of the vehicles had switched sides to join the protesters. But it's not entirely clear if that is the reason the Russian flags are on display.

In Slaviansk, north of Kramatorsk and about 100 miles from the border with Russia, pro-Russian militants now appear to be in control of the town, according to CNN's Nick Paton Walsh on the ground.

The atmosphere seemed more relaxed than it was a few days ago, with many residents apparently welcoming the presence of pro-Russian forces and their apparently seized military vehicles.

On the road toward Slaviansk, CNN's Phil Black encountered a heavily fortified and well organized police checkpoint. Attack helicopters passed overhead and a big military staging point is in operation just up the road.

Despite the military activity, there has so far been no effort to move into the town itself, he said, where the pro-Russian protesters are digging in and consolidating their power.

The unrest is a major test for the new interim government, as it seeks to hold Ukraine together ahead of elections scheduled for next month and to avoid bloodshed.

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