Workers and engineers scrambled Wednesday to restore at least partial service to the country's biggest television stations in Moscow after a three-day blackout caused by a fire at the main broadcasting tower.

RTR state television and ORT public television were scheduled to resume broadcasting Wednesday night from a temporary transmitter fixed to the trunk of the fire-ravaged 540-metre Ostankino tower, the world's second tallest tower.

"Installing a transmitter and antennae at the height of 147 meters for RTR and ORT to resume joint broadcasting is a priority. We hope it is a matter of 24 hours," Deputy Mass Media Minister Mikhail Seslavinsky told private NTV television.

The two channels would have to combine their programs as the transmitter allows broadcasting on only one frequency.

Engineers have been working to restore transmission to more than 10 million viewers in Moscow and adjacent areas since Sunday, when a fire swept through the Ostankino tower, killing three people and blacking out television screens for the first time in decades.

President Vladimir Putin ordered normal service to be restored within a week.

Psychologists have said the television blackout could have negative consequences for thousands of people addicted to daily viewing. Many spend up to five hours a day watching television.

The authorities initially said it would take at least a week to resume broadcasting. Their emergency plan was to install transmitters on top of the huge Stalin-era Moscow State University building, which stands on a hill in the capital's southwest.

The decision to start emergency broadcasting from Ostankino was made Tuesday after it became clear the tower was not as badly damaged as initially thought, and many cables in its lower part remained in working order.

Managers of NTV television, which has been piping its news programs to millions of Muscovites through a cable network owned by its parent company, Media-MOST, have accused the authorities of giving priority to state television.