Very hard to say. Obviously tougher action by the security services last night (Kiev time). Link to a live TV feed here, opposition source with English commentary, but more than that I don’t know.

Another feed here (in Ukrainian).

UPDATE: And a link to Espreso TV. Was showing live footage. Now (as I write) commentary. Cyrillic script in the left (again at the moment) reads ‘revolution’.

The Kyiv Post is updating its page on a regular basis.

Reuters:

Ukrainian riot police early on Wednesday poured into Kiev’s Independence Square, confronting opposition leaders and protesters demonstrating against a government decision to rebuild trade ties with Russia rather than move closer to the European Union.
Black-helmeted police entered the square in the heart of the snowbound capital where the demonstrators have been camping out for the past 10 days, tearing down barricades erected by the protesters.
Clashes broke out as police tried to detain some of the protesters. On one of the main streets leading into the square, a large group of protesters in hard hats, appointed to protect the demonstrators, held back a separate unit of riot police.
In emotional scenes, priests intoned prayers from a stage on the square and urged police not to use violence. Ruslana, a Ukrainian singer, called from a loud hailer: “Do not hurt us!”
Some protesters held mobile phones in the air like candles and sang the national anthem, while church bells rang out from a cathedral about 2 km (about 1 mile) away as in times of danger centuries ago….