Has the Cuban Government Blocked Twitter on the Island?

For some time now Cuban bloggers have been using the SMS feature of their cell phones to make posts to their twitter account (as they do not have regular access to the internet to make the posts nor smart phones with twitter apps)

Recently acclaimed Cuban blogger Yoani Sanchez published this to her twitter page :

#twitter debe aclarar si su servicio nos ha censurado publicacion de tweets por sms o si ha sido el gobierno de#cuba que nos ha bloqueado
23 minutes ago via web

Translation: Twitter should clarify if they've censored the publishing of our tweets through SMS or if the Cuban government has blocked us

#cuba Bloquearon la publicacion desde moviles cubanos a twitter. Parece que pusieron el filtro aqui dentro.1 amigo publica por mi este tweet
about 3 hours ago via web

Translation: Cuba blocked the publication of twitter messages from Cuban mobile phones. It looks like they've put a filter. A friend is publishing this tweet for me.

There has been no confirmation as to whether she is correct and the government is blocking the signals or if it is a technical problem with twitter and/or Cuban cellphone service. Should it be true this would be a serious blow to many Cubans who use this technology as a vital lifeline to the world. Check back here for more info on the story as information comes in.