The effects of a stand-off between Kenyan forces and gunmen at a Kenyan university was revealed on 6 April, when security officials took media to the campus for the first time after the attack.
Gunmen from the al Qaeda-aligned group killed 148 people on 2 April when they stormed the Garissa University College campus.
Students' clothes and shoes were scattered around the heavily damaged campus. Bullet holes were seen in the walls of dormitories. Walls and floors were still stained with blood.
Al Shabaab has killed more than 400 people on Kenyan soil in the last two years, including 67 during a siege at Nairobi's Westgate mall in 2013, piling political pressure on President Uhuru Kenyatta that intensified with last week's killings.
Kenya has struggled to stop the flow of militants and weapons across its porous 700km border with Somalia, and the violence has also damaged the economy by scaring away tourists and investors.
One of the four gunmen in the Garissa attack was the son of a Kenyan government official from Mandera county, which borders Gedo. Abdirahim Abdullahi, an ethnic Somali, was reported missing by his father after he crossed into Somalia to join al Shabaab. All four gunmen were killed in the siege.
Kenyatta said on Saturday the planners and financiers of Islamist attacks were "deeply embedded" within Kenyan society and urged the Muslim community to do more to root out radicalisation.
Garissa was the most deadly attack on Kenyan soil since al Qaeda bombed the US embassy in Nairobi in 1998, killing more than 200 people and wounding thousands.