Tensions are high among students after an Islamist attack on a Kenyan college 10 days ago which left 148 dead.
Meanwhile activists criticised Kenya for ordering Somali refugees home.
Human Rights Watch Africa Deputy Director Leslie Lefkow said justice for the victims of the attack in Garissa - by members of the Somali militant group al-Shabab - would not be served by forcing more than 500,000 Somalis in the Dadaab refugee camp to leave Kenya.
"Instead of scapegoating refugees, Kenya is legally obliged to protect them until it is safe for them to return home and should identify and prosecute those responsible for the killings in Garissa," she said.
UNHCR Kenya chief Emmanuel Nyabera described the possible relocation as a "logistic challenge".
The remarks follow calls on Saturday by Kenya's Deputy President William Ruto to close Dadaab, the largest refugee camp in Africa.
Mr Ruto said UNHCR had three months to close Dadaab and make alternative arrangements for its residents - otherwise, Kenya would "relocate them ourselves", he said.
Dadaab was set up in 1991 to house families fleeing conflict in Somalia. Some people have been living at the site for more than 20 years.
The Nairobi University blast happened at about 04:00 local time (01:00 GMT) on Sunday.
Reports say there were multiple explosions, or a prolonged sound, prompting fears of a terrorist attack and sending many students into a panic.
Some avoided using the entrances to their hostels, thinking that al-Shabab militants were occupying them, and jumped from windows, some as high as the 6th floor.
One man died after jumping and several other students were critically injured. Many suffered cuts and broken limbs.
The BBC's Milton Nkosi in Nairobi says everyone in Kenya has been touched by the attack in Garissa on 2 April, with questions asked about security lapses and the government's response to the attack.
Students have held protests against the lack of security on campuses.
Al-Shabab has promised a "long, gruesome war" against Kenya.
The group said its attacks were in retaliation for acts by Kenya's security forces, who are part of the African Union's mission in Somalia against al-Shabab.