Moscow cited unspecified information to back its assertion about the plans to arm the opposition, but did not say what that information was.
Witnesses say people there were protesting disputed President Nicolas Maduro's efforts to keep humanitarian aid out of the country. In recent years, Pacaraima has received thousands of Venezuelans crossing the border in search of food and medicine.
"A unsafe provocation, instigated and led by Washington, is planned for February 23", foreign ministry spokeswoman Maria Zakharova said, pointing to efforts by opposition leader Juan Guaido to pick up U.S. aid being stockpiled on the Colombian border.
Guaido, who on Thursday set out from Caracas in a convoy of trucks to personally bring in aid from the border, called on the military to arrest those responsible for the killings, "or you will be responsible".
Aside from the events in Colombia, they also hope to get humanitarian assistance delivered by sea and through Venezuela's remote border with Brazil.
Venezuelan singer Carlos Baute, one of 30 stars gathered by Branson to perform during the six-hour concert, said he was there "to open a humanitarian channel" for the delivery of aid.
The border city of Cucuta in Colombia played host to a concert organised by British billionaire Richard Branson on Friday, aimed at raising money for people in neighbouring crisis-stricken Venezuela.
Here, Chavismo, the brand of socialism popularized by Chavez, is still a force, strengthened in reaction to the growing power of the opposition, backed by the USA and over 50 other countries.
Maduro has said Russian Federation was providing 300 tonnes of aid but Moscow has not provided details.
At least two civilians have died in Venezuela and about a dozen more were injured in a confrontation with security forces near the national border with Brazil Friday. A concert known as Paz Sin Fronteras - Peace Without Borders - was held in 2008 after a diplomatic flare-up that drew Venezuelan troops to the Colombia border.
The bloodshed contrasted with the festive ambiance at Branson's "Venezuela Aid Live" in Cucuta. To all the military: "between today and tomorrow, you will define how you want to be remembered". Maduro earlier this week announced a three-day "Hands Off Venezuela" concert to last until Sunday but few details of the line-up or schedule have been released.
Yet the Venezuelan government overnight soldered three shipping containers, which it has been using to block the traffic lanes on the never-used Tienditas road bridge, to the bridge itself, Colombia's migration agency said on Friday.
Tons of aid supplies sent by Venezuelans in the U.S. have been held up on the Dutch Caribbean island of Curacao after Venezuelan authorities closed air and sea routes to the island.