"Western countries are involved in the war"/ The Russian spokesman breaks the 'bombshell' statement and makes a strong warning: On our land there are...

Russia continues to threaten the West, claiming that US-made weapons have been used by Ukraine to attack Russian areas.

Russian President Vladimir Putin's spokesman Dmitry Peskov has said it is "no secret" that US military equipment is being used against Russian forces in both Ukraine and Russia.

Kremlin spokesman Peskov's statement comes as the Pentagon launched an investigation into claims that US armored vehicles were used in the raid in the Russian city of Belgorod, about 25 miles from the border with Ukraine.

Footage purportedly taken during the Belgorod attack showed at least three US-made mine-resistant ambush protected (MRAP) vehicles being used during the raid.

The raid was reportedly carried out by a pro-Ukrainian militia made up of Russian citizens, but Pentagon spokesman Brigadier General Patrick Ryder said the US government had "not approved any third-party transfers of equipment to paramilitary organizations".

General Ryder added that Kiev had also not "requested" any such transfer.

"It is no secret that this equipment is being used against our army... and it is no secret for us that the direct and indirect involvement of Western countries in this conflict is increasing by the day," Peskov said.

Denying allegations that the attack in Belgorod was carried out by Ukrainian special forces, Ukrainian national security adviser Oleksiy Danilov told CNN that the insurgents and fighters "are Russian, it's their country and they have a right to be there."