Another witness said that at first the noise from the explosion sounded like an earthquake, before he began to see palls of smoke and alarms went off.
One hotel guest named Intan told Indonesia's TV One that the explosion in the Ritz-Carlton had destroyed a large area of the hotel's first floor.
"I was having breakfast on level 16, I heard an explosion and went down to the first floor and it was a mess. I saw foreigners all bloody, about three to five of them, badly wounded," she said.
"The building moved a lot and there was a lot of smoke"
Cho In-sang, a South Korean national who was staying at the Ritz-Carlton, recalled large pieces of debris falling from the roof as the explosion went off.
"I don't remember exactly but suddenly the ceiling is falling down and the sound was big," he told AFP at the Metropolitan Medical Centre hospital.
Cho, who suffered cuts and scratches on his arms and legs, said hotel staff had put him in a car and driven him to hospital.
Another European guest who was staying at the Ritz-Carlton told Indonesia's Global TV that the building had shaken violently when the bomb went off.
"The building moved a lot and there was a lot of smoke," he said, adding that there was mass confusion in the minutes after the blast.
Witness Alex Asmasubrata, who lives near to the hotel, told Al Jazeera that he saw several foreigners covered in blood in the immediate aftermath of the explosion at the Marriott.
"There were also other bodies lying nearby, and I had to come and help because there was no one at the scene immediately after the blasts," he said.
"All I could see was blood everywhere, and the injuries of what mainly were foreigners."