Broadcasts to Ethiopia by the US government's Voice of America (VOA) radio are being jammed once again.
The deliberate interference seems to have resumed in August, coinciding with a period of violent anti-government protests by the country's two main ethnic groups.
VOA broadcasts via shortwave in Amharic, Ethiopia's national official language, as well as in Oromo (spoken by the largest ethnic group) and Tigrinya (used in the north and in neighbouring Eritrea).
The broadcaster has responded to the jamming by boosting its broadcasts. It has added an extra 30-minute daily programme in Amharic and is using two additional shortwave frequencies.
But VOA has not issued a public statement about the interference.
It is not the first time that VOA broadcasts to Ethiopia have been disrupted. Previous incidents have also coincided with times of political tension.
The US broadcaster was jammed ahead of elections in 2010, 2008 and 2005.
And other opposition and foreign radio and TV broadcasters have also been subject to deliberate interference.
Satellite transmissions by ESAT, an opposition TV channel based in Amsterdam, have regularly been jammed.
In 2014, Saudi-based satellite operator Arabsat accused Ethiopia of "intentional jamming" which it said had affected many TV channels carried by its fleet.
It said its engineers had confirmed that the source of the interference originated from "Ethiopian territories".
The government has acknowledged that some jamming takes place, and has even defended the practice.
In 2010, then Prime Minister Meles Zenawi accused VOA's Amharic service of engaging in hate speech and said his government was ready to jam it.
Germany's external broadcasting service, Deutsche Welle (DW), also broadcasts in Amharic and has in the past been jammed, including in 2005 and 2007-08. At present, it does not appear to be suffering from interference.
The BBC has signalled that it will start shortwave broadcasts in local languages to Ethiopia and Eritrea.