Protestors wearing gas masks have constructed an improvised catapult to fight riot police in the capital of Ukraine, Kiev.

UKRAINIAN protesters have gone medieval in their battle with riot police, setting up an improvised catapult to shower officers with stones and firecrackers.

The latest move came as Ukraine's PM warned that security forces could use force to disperse protests after two nights of clashes that left hundreds wounded.

Azarov told Russian television that if "provocateurs'' did not stop, the authorities could act under controversial new laws that essentially ban large protests in Ukraine.

The protesters built the catapult from a large pile of long wooden poles they had carried to the site in central Kiev's Independence Square.

Once it was ready and fully operational, the rioters launched the catapult. After a few failed attempts, they showered the riot police with stones and projectiles, witnesses say.

Supporters managed to capture the operational catapult on film before the weapn was destroyed by police

Influential news site Dzerkalo Tyzhnia said that the authorities had already worked out a precise plan to regain control of the site of the intense clashes between protesters and the security forces.

Russian Foreign Minister Sergei Lavrov warned the situation in Ukraine was spiralling out of control after two months of protests over President Viktor Yanukovych's failure to sign a deal with the European Union.

Clashes raged in the centre of the Ukrainian capital until early on Tuesday, with demonstrators flinging Molotov cocktails and stones at security forces who hit back with stun grenades, rubber bullets and tear gas.

The day was relatively calm but sporadic clashes resumed late in the night Tuesday, an AFP correspondent said. However the exchanges lacked the ferocity of previous evenings.

"If the provocateurs do not stop then the authorities will have no choice other than to use the force set out under the law and ensure the security of our people,'' Azarov told Russia's Vesti 24 state news channel in an interview.

A new set of laws, which ban nearly all forms of protest in the ex-Soviet country and have enraged demonstrators, were officially published in the newspaper of the Ukranian parliament.

They allow for jail terms of up to five years for those who blockade public buildings and the arrest of protesters wearing masks or helmets.

Azarov added that he hoped there would be no need for the use of force to disperse the protests.

"We are hoping for common sense,'' he added. "People need to understand that they are being offered chaos and destruction.''