Azerbaijan has decided to ban from 1 January foreign radio broadcasts on the country's national frequencies.
The decision - taken by the Azeri National TV and Radio Council - will affect the BBC, Voice of America, Radio Liberty and Europa Plus.
Azeri officials denied opposition claims that the decision was political.
The move was criticised by the United States and the European security body, the OSCE, who both urged Baku to reconsider the ban.
"These media organisations play a crucial role in supporting democratic debate and the free exchange of ideas and information," said US State Department spokesman Gordon Duguid, quoted by the Associated Press news agency.
"This decision, if carried out, will represent a serious setback to freedom of speech, and retard democratic reform in Azerbaijan," he said.
The OSCE's media freedom representative, Miklos Haraszti, said "closing down FM news radio broadcasts that were among the few remaining sources of varied, public-service quality information is a serious step backwards for an OSCE democracy".
The head of the Azeri National TV and Radio Council, Nushiravan Magerramli, said earlier that the ban "has nothing to do [with politics]".
"The issue here is to bring the practice in line with legislation," he told Azerbaijan's Day.az website.
An official from President Ilham Aliyev's administration said Baku was "not closing down foreign radio stations".
"But we want their activities to be regulated according to international practice," Ali Hasanov added.
Azeri officials said foreign stations could broadcast via satellite, internet or cable. But the OSCE argues that Azeris have less access to those options than to FM radio.
European human rights groups and the Azeri opposition have accused President Aliyev of stifling democracy and media freedom in the oil-rich former Soviet republic.
Mr Aliyev - who took over as president from his father Heydar in 2003 - denies the accusations.