Kenyans are set to stage a rally for greater national security following a recent massacre by al-Shabab militants at a university in Garissa County.

The march will begin in the capital city of Nairobi on Tuesday, the final day of mourning for the 148 people killed by the al-Qaeda-linked militants on the Garissa University campus.

It took Kenyan special forces units seven hours to reach the university, located some 365 kilometers (225 miles) away from the capital last Thursday, when al-Shabab gunmen lined up the students in the dormitory and executed them.

The attack, Kenya’s deadliest in decades, claimed the lives of 142 students, three police officers and three soldiers.

Al-Shabab militants have said the attack was carried out in revenge for Kenya’s military operations in Somalia. The group has also threatened more bloodshed.

Kenyan President Uhuru Kenyattahas has pledged that he would retaliate “in the severest way possible” against al-Shabab militants for their April 2 assault.

On Monday, Kenyan military aircraft pounded two camps of al-Qaeda-linked al-Shabab militants in southern Somalia.

The militants have carried out a string of revenge attacks in Kenya as well as neighboring Uganda over their participation in the African Union Mission to Somalia (AMISOM).

Back in September 2013, the Westgate Mall in Kenya's capital city, Nairobi, was attacked and around 70 people died in a four-day standoff at the site. Al-Shabab militants claimed responsibility for the attack.

Somalia has been the scene of deadly clashes between government forces and al-Shabab militants since 2006.

The militants have been pushed out of the Somali capital, Mogadishu, and other major cities in the country by government forces and the AMISOM, which is largely made up of troops from Ethiopia, Uganda, Burundi, Djibouti, Sierra Leone, and Kenya.