The Cuban government is blocking calls to U.S. and Spanish telephone numbers once described as a 911 service for dissidents — a system they could use to swiftly report abuses to supporters abroad.

Hablalo Sin Miedo — Say it Without Fear — allowed Cubans to record voice messages of up to three minutes that were later posted on the system’s blog and automatically emailed to those who signed up, mostly other activists and journalists.

Launched last spring by a Cuba-born Florida International University graduate, the system borrowed a page from a Google and Twitter facility established after Egyptian President Hosni Mubarak shut down Internet access during the Tahrir Square riots.

It was receiving hundreds of calls per month with reports that the official media in the communist-ruled island would never publish, from arrests of the dissident Ladies in White to the damages caused by Hurricane Sandy last month and cases of corruption.

But starting on Oct. 29, its lines were blocked by Cuba’s government-owned telecommunications monopoly, ETECSA. Its U.S. number was blocked first, and when the system was switched to a number in Spain, that was blocked also.

ETECSA even blocked calls from Cuba to his personal phone, said the FIU graduate, who asked for anonymity because he wants to keep his Cuba activism separate from his job.

“We are exploring alternatives to re-establishing the service. We will soon announce new ways in which it can be used again,” the graduate wrote Thursday in an email to El Nuevo Herald.

“The fact that they have blocked Hablalo sin Miedo confirms its usefulness for Cuban activists and average Cubans who trusted us to tell the stories that the Cuban government wants to silence,” the email added.

Dissidents can still send fast messages using the Twitter system, but the outlook for finding an alternate way of sending voice messages abroad is unclear because all telephone calls in Cuba must go through ETECSA.

The Hablalo facility was being used most heavily in recent weeks by members of the Cuban Patriotic Union, a dissident group in eastern Cuba that has grown to be one of the most active opposition organizations on the island.

Also using the system have been members of the Cuban Network of Community Communicators, a group headed by dissident Martha Beatriz Roque that focuses on reports of neighborhood-level issues.

Roque said Cubans trying to call Hablalo Sin Miedo get a message saying the number is “temporarily disconnected.” The same message is often heard when Cuba’s State Security agents block calls to or from dissidents’ cell phones.

Google and Twitter established the Speak2Tweet system after Mubarak shut down the on-ramps to the Internet during the Arab Spring revolt there last year. The system received hundreds of thousands of calls, which were then posted on the Web and retransmitted as Tweets.

Calls to Hablalo Sin Miedo were fewer because phone calls from Cuba to the United States costs about $1 per minute — a costly fee in a country where the average monthly wage officially stands at about $20.

But foreign supporters of dissidents could pre-pay money into the accounts of Cuban cellular phones so they could be used to call the facility, and the system was at least theoretically available in case of emergencies.