Under the new guidelines, officials cannot remove the SD cards used in polling booth cameras immediately after voting ends, and concerned officials will only be permitted to dismount the cameras, which must then remain under the supervision of the sector officer, an official told news agency PTI.

"The SD cards can be removed only at the designated Data Collection and Receiving Centre in the presence of the Assistant Returning Officer," he said.

All video footage captured during polling must be preserved securely and systematically, the election official said.

"No member of the polling party or Booth Level Officer (BLO) can leave the polling station until the camera equipment has been fully dismounted," he said.

A trial run of webcasting for the second phase of polling will begin at 10 am on Friday, the official said.

"The exercise will be conducted in three shifts," he said.

West Bengal registered a record 92% voter turnout in the first phase of the assembly polls held on 23 April.

Voting was held in 152 seats spread across 16 districts of West Bengal amid unprecedented security to decide the electoral fate of 1,478 candidates, including 167 women.

The election for the remaining seats in the 294-member assembly will be held on 29 April. The results will be announced on 4 May.

The contest in West Bengal is considered largely bipolar. The ruling Trinamool Congress faces a resurgent Bharatiya Janata Party (BJP).

(With agency inputs)