The Cuban government is blocking text messages that contain words such as "democracy," "human rights," and "hunger strike," according to an investigation from local dissidents. In a Spanish-language report published last week, prominent blogger Yoani Sanchez and journalist Reinaldo Escobar found that the government is filtering 30 keywords and blocking the transmission of any texts that contain them.

Reuters later confirmed that messages containing the Spanish words for "democracy" and "human rights" did not reach their destination, nor did those containing Sanchez's name or "Somos Mas": an opposition group that worked on the investigation. Texts that included the word "protest" were transmitted, the agency reported on Tuesday, and those that were blocked were marked as "sent" on the sender's phone.

"It just shows how insecure and paranoid the government is."

It's not clear how long the communist government has been filtering keywords and blocking texts, and activists suspect that there may be more terms that it is targeting. Cuba has long been accused of committing human rights abuses, including arbitrary detentions and restrictions on freedom of speech. "We discovered not just us but the entire country is being censored," Eliecer Avila, the head of Somos Mas, tells Reuters. "It just shows how insecure and paranoid the government is."

Telecommunications services have long been extremely restricted in Cuba, where only around five percent of the population have home internet access. A greater proportion accesses the web through Wi-Fi hotspots, but prices remain prohibitively high for many, and the government heavily censors websites and media.

The island nation has taken steps to improve internet access, after it agreed to normalize relations with the US in 2014. Earlier this year, the government said it will bring broadband access to some Havana neighborhoods, as part of a pilot program, after previously announcing plans to create 35 Wi-Fi hotspots across the island.

The country still has the lowest mobile phone penetration rate in Latin America, according to Freedom House, though that figure has been rising due to recent fare cuts implemented by the state-owned Telecommunications Company of Cuba S.A (ETECSA). By the end of 2014, about 22 percent of the population owned a mobile phone, yet most are still unable to access the web through the devices, and costs remain high. Reuters could not reach ETECSA for comment on the reported text message filtering.