Ukrainian President Viktor Yanukovych has sacked the head of the armed forces, Col Gen Volodymyr Zamana, the president's website said, according to BBC News.

The move Wednesday, Feb 19, comes after the most intense violence in Ukraine's three-month crisis turned Kyiv into a battle zone.

Earlier the state security service announced it was launching a nationwide "anti-terrorist" campaign, to deal with a growing "extremist threat".

There was a suggestion the armed forces could be deployed for the first time.

Col Gen Zamana has been replaced by the commander of Ukraine's navy, Admiral Yuriy Ilyin, by presidential decree, Yanukovych's website said.

It comes after the most deadly violence in Ukraine's post-Soviet history erupted on Tuesday and overnight.

At least 26 people died, mainly in Kyiv, as protesters wielding petrol bombs and paving stones tried to defend their encampment in the central Independence Square from police using rubber bullets and stun grenades.

A crisis triggered by President Yanukovych agreeing closer ties with Russia in favour of the EU has, since late November, fostered a militant protest movement intent on seeing him ousted from power.