Attacks are continuing in Slaviansk, Mariupol, and other different places in Southeastern Ukraine, as well as the attacks carried out by militants in masks, who are acting ruthlessly," Lavrov said at a press conference, Voice of Russia reported.
"And, you probably hear more and more calls for Russia to save them from this lawlessness. They are putting us in a really difficult situation," he added.
A reporter asked Lavrov a question on statements by Kiev and the West that the presence of Russian weapons in Southeastern Ukraine proves Russia's involvement.
"This argument, I think, is just ridiculous, because there were never other weapons there. Russian weapons are everywhere in the country," Lavrov said.
A curfew has been announced in the Eastern Ukrainian city of Slaviansk after a group of unknown gunmen launched a deadly attack on a checkpoint near the city on Easter Sunday.
The leader of pro-federalization protesters, Vyacheslav Ponomaryov, who has been serving as the city's acting mayor, said the attack came in violation of the cease-fire announced ahead of Easter celebrations, and called on Russia to send peacekeepers to the region.