Update (7 November 2012):
The earthquake was also felt strongly in neighbouring Mexico and El Salvador.
Many users, like Nuestro Diario (@NuestroDiario) [es] and Esner Navarro (@esnernavarro) [es], are sharing photos of the damage in San Marcos, where at least eight people have died, according to the latest reports [es] by Prensa Libre.
Guatemalan President Otto Pérez Molina (@ottoperezmolina) [es] has been using Twitter to send updates on the situation. These are his latest tweets at the time of writing this post:
@ottoperezmolina: Se declara alerta roja nacional, se suspenden actividades públicas y se recomienda evacuar edificios.
@ottoperezmolina: We are declaring a national red alert. Public activities are suspended and we recommend evactuating buildings.
@ottoperezmolina: Se trabaja para poder brindar ayuda a las personas afectadas. Estamos a la espera de datos oficiales.
@ottoperezmolina: We are working to bring help to those who have been affected. We are waiting for official information.
The Red Cross in Guatemala (@CRGuatemalteca) [es] is also sharing information on Twitter.