Moscow - A Russian security official said up to 40 shells fired by Ukrainian forces fell on Friday on the Russian province of Rostov near the border with eastern Ukraine where Kiev is fighting pro-Russian separatists.
Vasily Malayev, a regional representative of Russia's Federal Security Service branch devoted to border security, was quoted by Russian news agency Interfax as saying that 30 shells had landed in a village in the region.
"There are no victims or casualties as a result of the shooting on Russian territory from the Ukrainian side. Around 30 artillery shells have been launched onto the territory of Rostov province," Interfax quoted him as saying.
He earlier told state Ria Novosti news agency around 40 shells had come across the border.
Both Moscow and Kiev have accused the other of shooting across the border, and Ukraine says missiles shot from Russia may have downed two of its fighter jets this week. Both Kiev and Moscow deny the accusations.
Moscow warned earlier this month of "irreversible" consequences after cross-border shelling that hit two houses in Rostov province, killing one man.
Russia's Chief of General Staff was quoted as saying by Interfax that it had proof that Ukraine had used phosphorus bombs that can kill through burns or smoke inhalation.
Earlier allegations of the use of the weapon were never proved and Kiev quickly denied this accusation.
"It's complete nonsense. We don't use phosphorus bombs. We simply don't have them. We use flares, but they have no relation to phosphorus bombs," Kiev's military spokesperson Vladislav Seleznyov said.