Pope Francis has appealed to Somali Islamist militants who killed 148 people at a Kenyan university last month to stop their brutality and "come to their senses".

He told bishops serving in Kenya visiting the Vatican that he prayed for those killed by acts of terror, ethnic and tribal hostilities in Kenya and elsewhere in Africa. The bishops included Mgr Paul Darmanin and Mgr Joe Alessandro, bishop and Coadjutor Bishop of Garissa diocese respectively. 

"I think most especially of the men and women killed at Garissa University College on Good Friday," the leader of the world's 1.2 billion Catholics said.

"May those who commit such brutality come to their senses and seek mercy."

The gunmen hunted down Christians while sparing Muslims in that attack. Francis has repeatedly expressed alarm about Christians being targeted for their faith and condemned the beheading of 21 Egyptian Copts in Libya in February.

He urged the visiting bishops to work with Christian and non-Christian leaders to promote peace in predominantly-Christian Kenya.

Al Shabaab said Garissa was revenge for Kenya sending troops into Somalia to fight alongside African Union peacekeepers against the Islamist group.