Secret police agents abducted and beat award-winning blogger Yoani Sanchez, whose online reports chronicle the dark side of everyday life in communist Cuba, on her way to a march for non-violence, she said Saturday.

Three agents in street clothes snatched her and friend Orlando Luis Pardo off the street in the Havana district of Vedado.

"They beat me and then they shoved me into a car head first. They did not give me any explanation at any time, but it is clear their goal was to stop us from taking part in the march," Sanchez, who writes the blog "Generation Y," told AFP.

Two other friends of hers were ordered into police cars and released later, she added.

In an item on her blog, which is often critical of the Americas' only one-party communist system in which only state media are legal, Sanchez wrote an expose under the headline "A Gangland-style Kidnapping."

"It was a very violent episode," she wrote.

"They squeezed my wrists very hard, beat me in the back in the kidney area, and when people stepped in to do something, they said we were counter-revolutionaries."

The advocacy group Human Rights Watch condemned the attack in a statement that said "Cuban authorities should cease all attacks on human rights defenders, journalists, bloggers and civic activists.

"The international community should condemn attacks on those who peacefully exercise their basic rights to freedom of expression, opinion, and assembly in the strongest terms," it said.

"Cuban authorities are using brute force to try to silence Yoani Sanchez's only weapon: her ideas," said Jose Miguel Vivanco, Americas director of Human Rights Watch. "The international community must send a firm message to Raul Castro that such attacks on independent voices are completely unacceptable."

Sanchez, winner of the Maria Moors Cabot 2009 award and Ortega y Gasset Prize awarded by Madrid's El Pais, said she was not seriously injured and was released half an hour after the arrest.

"Clearly, the beating hurts even more a day later; I am still really affected by all of this, but it is not going to stop me from writing my blog," Sanchez said.

Cuban authorities say Sanchez and all other political dissidents are "mercenaries" in the pay of the United States and other western countries.