Students at Kenya's Garissa university awoke on Thursday morning to the sound of gunmen prowling the campus, shooting at their classmates. Nearly 150 people were killed in what would become the deadliest attack yet by al-Shabab militants in Kenya.
"All I could hear were footsteps and gunshots," student Collins Wetangula told the Associated Press news agency. "Nobody was screaming because they thought this would lead the gunmen to where they are."
"The gunmen were saying, 'Sisi ni al-Shabab,'" he said - Swahili for "We are al-Shabab."
The raid began at dawn - about 0530 local time (0230 GMT). Two Toyota Probox cars drove up to the university gates, according to Kenyan daily newspaper The Star. Five gunmen got out, wearing masks and jungle-style fatigues, the paper says.
They shot dead two guards at the gate and entered the campus. A labourer named Boaz Muanja told The Star he initially mistook the gunmen for police officers - until they began firing in his direction.
A student said she too mistook the armed men for police when she went to check on an explosion at the gates. "All of a sudden I saw them throw explosives... where the Christian Union members were praying," she said.
Inside the dormitories, the students realised they were under attack.
"We were asleep… when we heard several gunshots outside the hostel," said Augustine Alanga, an economics student interviewed by the BBC's Newsday radio programme.
Many of the students escaped, he said. Those who were left behind were taken hostage by the gunmen.
"It was horrible, my life was in danger… they were shooting at us with live bullets," he said. "Everywhere all over the school compound was gunfire."
An unnamed witness, interviewed by Reuters TV, also spoke of being awoken by the sound of firing. "Guys started jumping up and down, running for their lives," he said.
But some of the students ended up "going to where the gunshots were coming from". The others, he said, escaped to open ground and eventually fled the campus.
Mr Wetangula, the vice chairman of the university students' union, told the Associated Press news agency that he was preparing for a shower when he heard the gunshots. He immediately locked himself in a room with three other students.
He says he heard the attackers opening doors and asking people if they were Muslim or Christians. "If you were a Christian, you were shot on the spot," he said. "With each blast of the gun, I thought I was going to die."
He said the shooting became more intense, apparently as the gunmen themselves came under fire.
The students left the room when men in military uniform appeared at one of the windows, identifying themselves as Kenyan soldiers.
But Mr Wetangula said the escape was far from smooth. "We started running and bullets were whizzing past our heads... The soldiers told us to dive."
Later, he said, a soldier told him that al-Shabab snipers had been firing from the roof of a dormitory.
Another student said he noticed that the attackers were fully covered, "leaving just a slit for their eyes". He said he helped a group of students escape by jumping onto chairs placed outside open windows.
Outside the university, Kenyan journalist Dennis Okari tweeted that he had been told to take cover amid the sound of heavy gunfire and explosions. "Hundreds of students run out, some crawling," he wrote.
Kenya's security forces say the militants were eventually surrounded in a dormitory. Four of them died, apparently as their suicide vests were detonated. The fifth gunman was captured alive.
The attack is the bloodiest yet on Kenyan soil by al-Shabab militants, based in neighbouring Somalia. A female student told Al Jazeera that she had stepped over more bodies than she could count as she escaped.
James Karubiu, the father of a student, told the BBC that he had searched for his daughter in a mortuary, fearing she was dead because he could not get through to her mobile phone.
When she eventually sent him a text message, he learnt that she had spent 10 hours hidden in a closet. "She was just peeping, and seeing how people were being killed like animals," he said.
Many Kenyans are asking if the attack could have been anticipated, and if more could have been done to protect the university.
Grace Kai, a student at a nearby teachers training college, said strangers spotted earlier in Garissa town were suspected to have been terrorists. The college principal had also warned of strangers having entered the college, she told Reuters news agency.
But another witness, who gave his name as Geremano, told the BBC's Outside Source that students had told him they had not expected an attack on the university.