An advance party of Russia's invasion force left a trail of damage in its wake as clashes erupted inside Ukraine's capital Kyiv for the first time, amid rising fears the city is about to be stormed or come under siege.

The Ukrainian ministry of defence said the clash had been provoked by "an enemy sabotage and reconnaissance group". Russian forces first arrived on the outskirts of Kyiv on Thursday when waves of helicopter-borne troops assaulted the Gostomel airfield just outside the city, close to Obolonsky.

Some 200 Russian helicopters were involved in the operation at the airfield, also known as Antonov Airport, the Russian Defence Ministry says.

The ministry claimed that 200 troops from Ukraine's special units were killed, adding that there were no Russian losses, according to state news agency RIA Novosti.

We have not yet heard from the Ukrainian military - and the Russian account has not been verified.

The Russian Defence Ministry says: "The success of the landing force was ensured by suppressing all air defence systems near the landing site, full isolation of the area of military action from the air and active radio electronic warfare."