Critics of the Azeri government say the move is part of a wider campaign against freedom of speech.
The representative of the Organization for Security and Co-operation in Europe (OSCE) in Baku, Maurizio Pavesi, said he was deeply concerned about the closure of a broadcaster widely considered to be the most objective in the country.
Broadcasting ended when police surrounded the ANS building in the capital and officials switched off its transmitters.
The independent television station's last transmission was a black and white message saying broadcasts had been suspended.
It now plans to appeal against the move.
Coincidentally, ANS says its radio channel was taken off the air during a report about an Azeri newspaper editor who had been taken to hospital after a hunger strike.
He had been protesting about the threat and closure of the offices of Azerbaijan's leading opposition newspaper, Azadlig.
President Ilham Aliyev has denied there is a problem with freedom of speech in Azerbaijan and the Azeri authorities say they are simply enforcing the law.
ANS has also been at the centre of a dispute over the rebroadcasting of news programmes from foreign media companies.
By Public Radio of Armenia