Concern regarding information disorders has been magnified by the proliferation of social networks. Since its occupation of Crimea in 2014, Russia has been spewing disinformation both inside and outside its borders, giving rise to a hybrid conflict, which since 24 February 2022 has become an invasion. Faced with this flood of malicious information on social networks, fact-checkers assume the role of content curators, relying on contextualization, verification, and literacy improvement to reduce such noise. This work studies the Twitter activity of three Spanish fact-checkers (Newtral, EFE Verifica, and Maldito Bulo), to fight this new epidemic of disinformation. The sample (n = 397) was subjected to content analysis to study the evolution of the verifications and their reaction capacity, the purpose of their activity, the formats in which the content is presented, and their distribution and interaction as revealed by reactions on Twitter. The results reveal a rapid, albeit repetitive, response of the fact-checkers to the invasion, support from them to end the internationalization of hoaxes, a reliance on denials and contextualization rather than literacy improvement, unattractive formats, and a distribution and impact that demonstrate a greater reaction to sensational and emotive content.