After he heard Thursday night about the attack inside a mosque in New Zealand, Imam Mohammad Ali Elahi said he grew worried.

"I could not even sleep last night," Elahi, the religious leader of the Islamic House of Wisdom in Dearborn Heights, said. "It's really a sad day, a dark day."

But Elahi was determined to lead Friday prayers, the most popular gathering time for Muslims — and when the New Zealand shooter attacked, killing 49 worshippers.

The New Zealand shooting is one of the deadliest attacks against Muslims in a Western country in recent memory. Brenton Tarrant, a 28-year-old man born in Australia who is reported to have expressed white supremacist views, has been arrested and charged in the shootings; three others were arrested in connection with the shootings.

"This is not the time to give in," Elahi said inside his mosque Friday afternoon after prayers. "This is not the time of showing weakness, silence; our silence won't help us, it will hurt us. We have to come to prayer and show more devotion and more determination and ... show that we are not scared. If we don't come, we are giving a gift to the terrorists."

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Elahi's views were echoed in many of metro Detroit's Muslim communities, where there is anxiety but determination to keep on attending their houses of worship and practicing their Islamic faith.

There were increased patrols and police presence on Friday at some mosques in Michigan, including in Dearborn and Dearborn Heights, said police and faith leaders. At Elahi's Islamic House of Wisdom, there were two Dearborn Heights police officers near the entrance keeping an eye out.

Faik Nasser of Canton said he and his wife felt anxious Friday, but showed up for services at the Islamic House of Wisdom.

"He attacked humanity," Nasser said of the New Zealand attack. "He attacked all of the teachings of the great Abrahamic religions."

Nasser said the attacks are the result of increased Islamophobia. He criticized President Donald Trump for what he said are the president's intolerant views of Muslims and Islam.

During his Friday sermon, Elahi also criticized Trump, saying his "both sides" remarks are failing to criticize the threat of violent white supremacy. It "sends the wrong message," Elahi said.

A range of Muslim and Arab-American groups in metro Detroit sent out statements condemning the New Zealand attack, including the Islamic Institute of America in Dearborn Heights, the Islamic Center of America in Dearborn, the Arab American Civil Rights League in Dearborn and the American Human Rights Council in Dearborn.

The Catholic Archbishop of Detroit Allen Vigneron also released a statement, saying in part: "On behalf of the all of the Catholic faithful of southeast Michigan, I offer prayers and condolences to the Muslim community throughout the world, especially in New Zealand, as they mourn the horrific violence that unfolded Friday in two houses of worship."

Imam Hassan Al-Qazwini, the religious leader of the Islamic Institute of America in Dearborn Heights, asked "all Muslim communities in the U.S. to be vigilant during Friday prayers and call on U.S. law enforcement agencies to offer protection to houses of worship."

A vigil was planned for 7 p.m. at Al-Qazwini's mosque and another vigil was planned for 8 p.m. at the Islamic Center of America.

The cities of Dearborn and Dearborn Heights have several mosques and sizable Muslim communities: 2017 Census figures show that Dearborn's population is more than 46% Arab-American and Dearborn Heights is about 30% Arab-American, most of them Muslim.

"We urge Muslim communities to be vigilant, the threat is real," Imad Hamad, the Executive Director of the American Human Rights Council, said. "The massacre in New Zealand should shock us all into considering the root causes of such crimes."

U.S. Rep. Rashida Tlaib, who is Muslim, said in a statement: "This morning I tried to hold back tears as I hugged my two brown, Muslim boys a little tighter and longer. The painful loss of life based on hate makes me so angry."

In his sermon, Elahi said to help the victims through online fundraising sites. A Detroit-based online fundraising site led by Muslims, LaunchGood, said it has raised about $680,000 by Friday night for the victims of the New Zealand shooting and their families.

While Muslim communities are tense, they are hopeful, seeing the expressions of support from other faiths, said Elahi.

"All human beings are organs of the same body," Elahi said during his sermon. "When one member of the body is hurt, the entire body is hurt. ... We are sad, we are upset, but we are not losing our hope."

Drawing upon Muslim and Christian beliefs, Elahi added: "The Earth is dead with arrogance, the Earth is dead with injustice, the Earth is dead with injustice; but the life of peace, the life of justice, the light of love, the light of peace, the light of unity and brotherhood is coming."

Elahi urged prayers for the victims and "for the speedy healing of the wounded. ... Please continue your prayers for them."

Contact Niraj Warikoo: nwarikoo@freepress.com or 313-223-4792. Follow him on Twitter @nwarikoo. Reporter Micah Walker contributed to this report.