Video footage on Ukrainian television showed shocking scenes today of protesters being cut down by gunfire, lying on the pavement as comrades rushed to their aid.
Trying to protect themselves with shields, teams of protesters carried bodies away on sheets of plastic or on planks of wood.
Protesters were also seen leading policemen with their hands held high around the sprawling protest camp in central Kiev. Ukraine's Interior ministry says 67 police were captured in all. It was not clear how they were taken. An opposition lawmaker said they were being held in Kiev's occupied city hall.
Parts of the country, mostly in its western cities, are in open revolt against Yanukovych's central government, while many in eastern Ukraine favour strong ties with Russia, their former Soviet ruler.
At least 99 people have died this week in the clashes in Kiev, a sharp reversal in three months of mostly peaceful protests.
Now neither side appears willing to compromise, with the opposition insisting on Yanukovych's resignation and an early election and the president apparently prepared to fight until the end.
Dr Oleh Musiy, the top medical coordinator for the protesters, told the AP that at least 70 protesters were killed today and over 500 injured. He said the death toll from the day's clashes could well rise further.
There was no way to immediately verify his statement.
Earlier in the day, an Associated Press reporter saw 21 bodies of protesters laid out on the edge of the capital's protest camp.
