GARISSA, Kenya (AP) -- Somalia's Islamic extremist group warned Saturday of more attacks in Kenya like the assault on Garissa University College that killed 148 people.
"Kenyan cities will run red with blood," said al-Shabab according to the SITE intelligence monitoring group.
The Islamic militants said the attack on Garissa college was in retaliation for killings carried out by Kenyan troops fighting the rebels in Somalia.
"No amount of precaution or safety measures will be able to guarantee your safety, thwart another attack or prevent another bloodbath," said al-Shabab.
Following the extremists' threats, Kenyan President Uhuru Kenyatta vowed to take harsh measures against the Islamic militants.
In a nationally televised address, Kenyatta said his administration "shall respond in the severest ways possible" to the Garissa attack, which occurred Thursday when four gunmen entered a campus and slaughtered students. The military moved in hours later and the gunmen were killed.
"We will fight terrorism to the end," said Kenyatta. "I guarantee that my administration shall respond in the fiercest way possible."
Kenyatta said the country's "security forces are pursuing the remaining accomplices. We will bring all of them to justice." he said.
"We are also in active pursuit of the mastermind (of the Garissa attack) and have placed a reward for his capture," said Kenyatta, who declared 3 days of national mourning over the Garissa attack.
Five people have been arrested on suspicion of involvement in the Garissa attack, a Kenyan official said.
Kenyan security agencies arrested three people trying to cross into Somalia, said Interior Ministry spokesman Mwenda Njoka in a Twitter post. He said the three are associates of Mohamed Mohamud, also known as Dulyadin Gamadhere, a former teacher at a Kenyan Madrassa Islamic school who authorities say coordinated the Garissa attack. Kenyan authorities have put a $220,000 bounty for information leading to Gamadhere's arrest.
Two other suspects were arrested at Garissa college.
A survivor of the killings at Garissa University College was found on Saturday, two days after the attack by Islamic extremists killed 148 people.
Cynthia Cheroitich, 19, told The Associated Press from her hospital gurney that she hid in a wardrobe and covered herself with clothes, refusing to emerge even when some of her classmates came out of hiding at the demands of the gunmen from the al-Shabab group.
She was rescued shortly before 10 a.m., according to Kenyan officials.
Cheroitich said she didn't believe that rescuers urging her to come out of her hiding place were there to help, suspecting at first that they were militants.
"How do I know that you are the Kenyan police?" she said she asked them.
Only when Kenyan security forces had one of her teachers appeal to her did she come out, she said.
"I was just praying to my God," Cheroitich, a Christian, said of her ordeal.
Cheroitich appeared tired and thirsty, sipping on yoghurt and a soft drink, but otherwise seemed in good health.
She said she drank a body lotion because she was so thirsty and hungry while in hiding.
Authorities displayed the bodies of the alleged attackers before about 2,000 people in a large open area in central Garissa. The bodies lay on the bed of a pickup truck that drove slowly past the crowd, which broke into a run in pursuit. Soldiers monitored the crowd. There was shouting and clouds of dust rose as the vehicle left the area.
Spectator Yusuf Mohamed applauded the display, saying authorities wanted to "win the hearts of the people" and clear any doubts that the attackers had been killed.
Kenyan authorities initially said the attackers had been strapped with explosives that went off like bombs when they were shot, but investigators later said there were no suicide vests. The four bodies shown Saturday had wounds but were intact.
The bodies of many of those killed in Garissa have been transported to the capital, Nairobi, where grieving Kenyans gathered to view the remains of family members.
Odula contributed to this report from Nairobi.