The U.N. chief has expressed solidarity with Muslims world over during a visit to Cairo, denouncing hate speech and racism, as well as anti-Semitism.

The remarks by U.N. Secretary-General Antonio Guterres on Tuesday in the Egyptian capital came less than a month after the terrorist attack on New Zealand mosques killed 50 worshippers.

Guterres says "hate speech is entering the mainstream, spreading like wildfire through social media and radio."

He says that "in this time of difficulties and division, we must stand together and protect each other. Nothing justifies terrorism, and it becomes particularly hideous when religion is invoked. ... we must uphold and promote human dignity and universal human rights."

Guterres' comments came after his meeting with Egypt's top Muslim cleric Sheikh Ahmed el-Tayeb, the grand imam in Cairo.