Army personnel have been deployed at sensitive locations in the city along with the local police in view of the increased tension on the Line of Control, an official said on Wednesday.
Along with central paramilitary forces, Army jawans are guarding key railway stations, airport, the area outside the Western Naval Command headquarters and various defence establishments in Mumbai and neighbouring towns, he said.
Videos circulated on social media showed large vehicles being moved in the city. Some onlookers claimed they were anti-aircraft gun carriages but there was no official word on the vehicles' contents.
Police said they facilitated swift movement of defence vehicles from Thane to Mumbai Tuesday night.
"We received a request for assistance from the defence forces and we provided it," said a police official involved in traffic management.
In the most horrific terrorist attacks in the country's history, 166 people were killed and over 300 injured as 10 heavily-armed terrorists from Pakistan created mayhem in Mumbai on November 26, 2008.
The Western Naval Command is also on high alert, the official said.
The Command is gearing up for action in the deep sea if needed, adding the Coast Guard and Marine Police are keeping vigil along the state's coastline.
Mumbai Police too have been put on high alert after the Indian Air Force conducted air strikes at Jaish-e-Mohammed camps inside Pakistan early Tuesday morning.
"Police are on alert and prepared to face any situation. Nakabandi (vehicle checking) is going on in various parts of the city," he said.
The security at vital installations has been increased, he added.
Maharashtra DGP Datta Padsalgikar and Mumbai police commissioner Subodh Jaiswal attended a meeting convened by Chief Minister Devendra Fadnavis on Wednesday with opposition leaders and senior police officials in view of possible security threat to the coastal city.