Heavy security was deployed at several places in Mumbai and adjoining cities on Wednesday, a day after MNS chief Raj Thackeray urged people to play the Hanuman Chalisa on loudspeakers wherever they hear loudspeakers "blaring 'azaan'".
The morning prayers were offered peacefully at many mosques, an official said.
All senior police officials, including Mumbai Police Commissioner Sanjay Pandey, were out to take stock of the security deployment, he said.
Police were also deployed outside mosques at some places.
There was nakabandi (blockade) at various locations and vehicles were being checked since the early hours to avoid any untoward incident, the official said.
As a precautionary measure, the city police have already issued more than 1,600 notices under various sections of the Criminal Procedure Code, including 149 (for preventing cognisable offences), to MNS workers and others.
The police had also conducted meetings with maulvis and trustees of various mosques and asked them to follow the Supreme Court guidelines and rules related to noise pollution.
Heavy security was also deployed at many places in neighbouring in Thane and Palghar districts.
There was elaborate police bandobast near the Jumma Masjid in Mumbra township of Thane.
Some MNS workers had plans to play the Hanuman Chalisa near there, but they left after the 'azaan' was not heard outside the religious premises. Mumbra police station's senior inspector Ashok Kadlag said the situation was under control and there was no report of any untoward incident so far.
Deputy Commissioner of Police, Zone II, Bhiwandi, Yogesh Chavan also said the powerloom town in Thane was peaceful.