Ukrainian security officials on Monday said a plot to overthrow the federal government in Kyiv had been thwarted as Russia ramps up attacks on the capital city. 

Four Ukrainian civilians were detained over the weekend on suspicion of planning an alleged coup by seizing Parliament and announcing their intent to replace military and civilian leadership, said the Security Service of Ukraine (SBU) following an investigation that began in May.

Ukrainian officials have offered few details regarding the plot but said the "activists" were working under the guise of forming a peaceful rally in Kyiv on Sunday.

Despite dissident messages exchanged on social media, the majority of the participants of the event were allegedly unaware of the group’s intent to "force" the public to "choose a temporary government," claimed Ukraine’s Prosecutor General’s office in a Telegram post.

It is unclear if the group had any connections with Russian officials, though the SBU noted the scheme "would have played in Russia’s hands."

U.S. and European intelligence officials have accused Moscow of ramping up its covert campaigns against Kyiv and its international allies in a move to undermine support for Ukraine, reports said earlier this year. 

Russia has seen recent gains in Ukraine and security officials said Sunday that Russian President Vladimir Putin is taking a new approach when it comes to striking Kyiv. 

"The aggressor is testing new tactics – he is looking for the right time, methods and means," the Kyiv City Military Administration said in a post to Telegram. 

The administration pointed to the lack of ballistic and cruise missiles used in the latest strike on the city Sunday, but reminded citizens not to ignore air raid sirens that have plagued the city for more than two years. 

"No air alarm can be ignored," the administration said in its post. "Rockets are shot down, but the molecules do not disintegrate, and the debris poses a threat to human life."