NEW YORK >> U.N. Secretary-General Antonio Guterres went to the first mosque built in New York City today to show solidarity with the Muslim community, urging people everywhere “to reaffirm the sanctity of all places of worship and the safety of all worshippers.”

Speaking a week after the terrorist attacks on two mosques in Christchurch, New Zealand that killed 50 people, Guterres warned again that “around the world, we have seen ever-rising anti-Muslim hatred, anti-Semitism, hate speech and bigotry.”

“We need to act against extremism in all its forms — whether it targets mosques, synagogues, churches or anywhere else,” he added.

Guterres first spoke at Friday prayers in the mosque at the Islamic Cultural Center of New York and then addressed the media at its school. He was surrounded there by the imam and more than a dozen U.N. ambassadors from Muslim and non-Muslim countries including New Zealand and Australia, where the white supremacist who gunned down victims at the mosques was born.

In remarks at the prayer service, Guterres recalled that a worshipper who saw a stranger walk into one of the Christchurch mosques said “Hello, brother,” not knowing he was a terrorist.

“This is the spirit deeply embedded in Islam, a religion I so much respect — the face of love, compassion, forgiveness, mercy and grace,” the U.N. chief said.

But Guterres warned in his remarks afterward that “hate speech is spreading like wildfire,” that “social media is being exploited as a platform for bigotry,” and “many political movements are either openly admitting their neo-Nazi affiliation, or lip syncing their words, and cutting and pasting the symbols and images.”

“That cancer is spreading,” the secretary-general said. “It is our duty to find the cure.”

Guterres announced that he was asking Miguel Moratinos, head of the U.N. Alliance of Civilizations, to develop “an action plan” to ensure that all U.N. bodies are “fully engaged in support of safeguarding religious sites.”

He said governments, faith-based organizations, religious leaders and others should be involved in discussing actions that can prevent attacks “and guarantee the sanctity of religious sites.”

“The reason is clear: Mosques and all places of prayer and contemplation should be safe havens, not sites of terror,” Guterres said.