Jeff Mitchell, 44, arrived in Ukraine's capital on Wednesday night to cover the protests and described the dangerous atmosphere in Independence Square yesterday as a truce between protesters and police broke down.
Clashes between police and anti-government demonstrators in recent days have left almost 70 dead.
Mr Mitchell, from Alexandria, West Dunbartonshire, said: "When I arrived there seemed to be a real lull in proceedings. I think people might have been tired from the day before.
"But there's been a big push. The protesters have regained a large amount of the square, they've pushed the police back.
"The atmosphere is very aggressive, very tense.
"I don't feel safe, not when it's kicking off. You can hear the bullets flying about - it's not safe. The protesters are just using stones and Molotov cocktails. They've no weapons. It's the police who are shooting."
Mr Mitchell, a former Herald photographer who now works with the Getty agency, said there were "tens of thousands" of people gathered in the square.
He said the protesters appeared to be highly organised and determined to overpower the police.
"They're building new barricades to push the police back. One is under a sort of steel bridge, just behind the front line. In the square they're busy clearing up and moving all the cobbled stones they've taken from the side streets and putting them in bags and moving them to the frontline.
"There's chains of people moving bricks and burning tyres to the frontline.
"They use the smokescreen of the burning tyres to hide behind and conduct their battle. It's a real organised effort. They really want to win."
He added he had not witnessed any aggression towards the media by police, but doubted he would be able to take pictures from behind police lines.
Mr Mitchell, who plans to remain in the Ukraine at least until next week, compared the atmosphere to photographing Tahrir Square in Egypt on the first anniversary of the anti-Mubarak uprising.
"It was dangerous in different ways," he said. "This is dangerous because there's bullets and bricks flying around; Egypt was dangerous because they were slightly hostile to the media. There are similar numbers, though."