Updated

One hour into the debut of her Twitter account on Tuesday, Mariela Castro (@CastroEspinM) was engaged in a snarky duel of words with Yoani Sánchez (@yoanisánchez).

Largely unnoticed by much of the world so far, this Havana war of Tweets is a remarkable sign of the times.

Mariela Castro, who lives in Havana, is the daughter of Cuban President Raul Castro and the niece of Fidel Castro. Yoani Sánchez, who also lives in Havana, is Raul Castro’s most well-known antagonist on the Internet.

Earlier this year, Sánchez, 36, challenged Castro, an activist for gay rights, to a public discussion with her about tolerance, but insisted that the president’s daughter also address other kinds of rights in Cuba – such as the right to free speech, to elect political leaders and to travel abroad.

Castro, whose father’s government denounces Sánchez and other dissidents as traitors to the Communist revolution and pawns of the U.S. government,  did not respond to those requests. Cuban officials have denied Sánchez permission to travel abroad to receive several human rights awards.

Welcome to Twitter pluralism @CastroEspinalM. Here, no one can silence me, deny me permission to travel nor impede my entry

— Yoani Sanchez, in a tweet to Mariela Castro

“They tell me that Mariela Castro has opened an account on Twitter,” Sánchez tweeted on Tuesday about an hour after @CastroEspinM had posted some initial tweets that included an exchange of pleasantries with @Yohandry8787. “One question for her: When will Cubans be able to break free of [all] restraints?”

Sánchez then tweeted Castro: “Welcome to Twitter pluralism @CastroEspinalM. Here, no one can silence me, deny me permission to travel nor impede my entry.”

Castro, 49, responded: “Your focus on tolerance resurrects old power structures. To improve the value of your ‘services,’ you need to educate yourself.”

Sánchez nudged her again on her advocacy for gay rights, but not other rights the blogger says are oppressed in Cuba.

Sánchez shot over another Tweet: “Another little question for @CastroEspinM. How can you ask for selective acceptance for one issue. Acceptance is total, or not?”

As of 3:30 p.m., Castro had not responded directly to Sánchez’s tweet, except with this: “Friends who follow me, thanks for your messages. I appreciate also the mediocre-minded and bored for sharing my tweets with others.”

By nearly 4 p.m. Tuesday, Castro, who sometimes is discussed as a possible successor to her father for the presidency in Cuba, had 242 followers, and had posted seven tweets. Among the accounts she follows are those of Venezuelan President Hugo Chavez, Argentinian President Cristina Fernandez and various Cuban state-run media.

Sánchez, who has gained a near rock star status among human rights bloggers around the world, has more than 173,000 followers, as well as an account on Facebook.

She has been active on the Internet for several years, often relying on friends abroad to post her messages for her because of what she has said are government efforts to interfere.

Follow Elizabeth Llorente on Twitter: @Liz_Llorente

Elizabeth.Llorente@FoxNewsLatino.com

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