Speaking to Russian news agency TASS, Russian Ambassador to the UK Andrey Kelin said the weapons would be “destabilising”.
It comes as the delivery of the artillery and anti-ship systems has been announced by the Ministry of Defence.
Mr Kelin said: “Any supply of weapons is destabilising, especially those that [British Defense Minister Ben] Wallace spoke about.
“They aggravate the situation, make it even more bloody. These, apparently, are new, fairly high-precision weapons.
“Of course, they will be legitimate targets for our Armed Forces if they cross the Ukrainian border.”