Opposition sources in Ukraine say three people have been shot dead in clashes with police, in Kyiv’s worst violence for more than three weeks, Euronews reported.

The clashes broke out near parliament on Tuesday morning.

Protesters torched vehicles and hurled stones. Security forces – including the Berkut riot police – replied by firing rubber bullets as well as stun and smoke grenades from trucks and from the tops of buildings.

Dozens of people are reported injured, on both sides.

As well as the deaths, opposition medical sources said at least 150 activists had been hurt, 30 of them seriously.

Demonstrators had been trying to march on parliament ahead of a crucial debate but they were blocked from approaching the building by security forces.

Activists stormed, set fire to and briefly occupied a building belonging to President Viktor Yanukovych’s political party amid scenes described as “open warfare”.

It is three months since protests first broke out over Yanukovych’s rejection of an EU trade deal in favour of closer ties with Russia. They have since broadened into a revolt against perceived sleaze and corruption in his leadership.

The opposition are pushing for a vote on constitutional change to reduce his powers but as moves in parliament were thwarted, frustration spilled out onto the streets.