Explosions and heavy gunfire were heard as security officers engaged suspected terrorists on Wednesday at about 6am inside Grosvenor Hotel in the Dusit office complex.
Officers were seen advancing towards where the attackers are suspected to be hiding on the seventh floor of the building.
This comes after more than 50 survivors of the attack were successfully rescued and reunited with families who had been camping outside for more than 10 hours.
Most of the rescued were hiding on the first floor of the building under tables, chairs and in the washrooms.
According to accounts by the survivors, the security officers reached them at about 4am, identified themselves and escorted them out.
At least four ambulances were seen leaving the compound with the injured.
Many people are still camped on Riverside Drive, the road leading to the DusitD2 Hotel, as rescue operations continue amid heavy gunfire.
After the batch that was rescued at about 4am following heavy gunfire, no other survivors have been rescued.
It is feared that more people are still trapped on the seventh floor where security officers are still advancing towards.
The floor houses offices and part of the hotel.
Source: Daily Nation