Five international broadcasters have condemned the deliberate jamming of their broadcast signals this year in countries such as Iran that seek to prevent free access to information.

Voice of America joined the BBC, Deutsche Welle, Audiovisuel Exterieur de la France and Radio Netherlands Worldwide in signing a statement Wednesday, condemning the practice and calling for action to stop it.

In the statement, the five broadcasters say they have seen an escalation this year in the number of pressure tactics that have been used on the media accessed by audiences in Iran and other countries. They asked regulatory authorities to take action against those who deliberately cause interference to satellite signals on the grounds that this is contrary to international conventions.

Representatives of the five outlets discussed the issue at a meeting in London ahead of an international telecommunications union meeting in Switzerland.