NAIROBI, April 4 -- Kenyan President Uhuru Kenyatta on Saturday declared three days of national mourning during which the country's flag shall fly at half-mast, following Thursday's Garissa terror attack.

Kenyatta said in Nairobi that Kenya is in a profound state of mourning following the heinous attack and mindless slaughter of near 150 Kenyans.

"I want to assure the families that the government will provide all possible support to the victims," Kenyatta said.

The Garissa University terror incident was the worst terrorist attack on Kenyan soil since the 1998 U.S. Embassy bombing in Nairobi.

Kenyatta noted that security forces managed to killed four of the terrorists.

"I commend the three officers who paid the ultimate price in their selfless service to Kenya," he said, adding that the country' s security forces are currently pursuing leads on the remaining accomplices.

"We shall employ all means at our disposal to bring the perpetrators to justice. We are also in active pursuit of the mastermind of the attack, and have placed a reward for the information leading to his capture," he said.

The Kenyan leader said since the attack, Kenya has received many messages of condolence and strong expressions of support and goodwill from friends and people across the globe.

"This solidarity underlines the oneness of humanity and consensus that terrorism is a global threat requiring robust international partnerships," he said.