An Islamic advocacy group on Thursday called for state and federal investigations into phone threats directed at a mosque near the New Jersey home of New York City terrorism suspect Sayfullo Saipov.

The threats were revealed the same day NYPD officials said the Uzbekistani truck driver likely acted alone when he planned and carried out Tuesday's carnage. The rampage in Lower Manhattan left eight people dead and 12 wounded.

This undated photo provided by St. Charles County Department of Corrections via KMOV shows the Sayfullo Saipov. A man in a rented pickup truck mowed down pedestrians and cyclists along a busy bike path near the World Trade Center memorial on Tuesday, Oct. 31, 2017, killing several.

The Islamic Center of Passaic County reported receiving eight threats, but officials would not say whether there was any evidence that the threats were credible.

Omar Awad, president and CEO of the Islamic Center of Passaic County, said the calls were profane. Callers stated, "We're gonna come get you and kill you," and, "We're going to burn down your place," he said. Others said, "Get out of the country," followed by curses and slurs, Awad said. 

The Paterson police have conducted extra patrols and stationed a unit at the mosque during prayer time, Awad said, adding that the mosque has increased the hours of its own private security guards.

Initial reports indicated that threats were also made against the Omar Mosque, which is around the corner from Saipov's home. But authorities later said they had confirmed threats only at the Islamic Center of Passaic County.

“We urge local, state and federal law enforcement authorities to treat this and all the other cases of threats and violence targeting American mosques with the seriousness they deserve and to bring the perpetrators to justice,” said Council on American-Islamic Relations New Jersey Executive Director Jim Sues in a Facebook post. He asked that law enforcement "be especially vigilant at a time when the risk of backlash against the Muslim community is most severe.”

Paterson Police Director Jerry Speziale confirmed the threats but declined to discuss details. The Passaic County Prosecutor’s Office and the U.S. Department of Homeland Security have been notified, Speziale said.

The Uzbekistani truck driver likely acted alone when his rampage through a Manhattan bike trail killed eight people and wounded a dozen more, a New York City police official said Thursday.

John Miller, NYPD's deputy chief of intelligence and counterterrorism told CBS This Morning that there was no evidence thus far to "make us believe that there was anyone else involved" in the attack

"But I caution that we are only a day or two into this," Miller said.

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The FBI had said Wednesday it was looking for Mukhammadzoir Kadirov in connection with the case, then said a short time later that he was found. Kadirov has not been arrested and knew Saipov only as a fellow Uber driver, the Associated Press reported, citing Kadirov's family members.

Kadirov released a statement on the attack to AP: "It is so sad and unbelievable. This not from our religion. It is not acceptable. We as Muslims completely reject this kind of actions. No human being who has a heart can do this.”

NYPD Officer Ryan Nash halted Saipov's attack when he shot the suspect in the stomach. Saipov appeared in court Wednesday in a wheelchair, handcuffed with his legs in shackles.

Authorities said Saipov, ordered held without bail, meticulously planned the assault and left multiple notes proclaiming that the "Islamic State would endure forever." Scores of Islamic State propaganda videos were found on his phones. Miller said that fits a common mold of radicalization occurring online.

Miller said capturing Saipov affords investigators an opportunity to determine "what brought (him) to this point." He said authorities, despite constant discussions with mainstream Muslim leaders, remain mystified on how to stop the "arc of radicalization."

"This is something that has vexed us since 9/11," Miller said. "We have no effective counter message."

Saipov told investigators after his capture that he "felt good" about what he had done, even asking to hang an Islamic State flag in his hospital room. President Trump took note on Twitter, repeatedly proclaiming Saipov should receive the death penalty. 

Trump also suggested Saipov be imprisoned at Guantanamo Bay, but later tweeted that "there is also something appropriate about keeping him in the home of the horrible crime he committed. Should move fast."

Attorney Gen. Jeff Sessions on Thursday added his tribute to the long list of glowing testimonials to the efforts of Nash.

"His quick response, courageous actions under pressure prevented the attack from getting worse," Sessions said. "He is rightly regarded as a hero today, not just in New York but across America. He symbolizes the best in law enforcement."

Nash himself held a brief news conference Wednesday, saying he and fellow officers were "just doing our job, like thousands of officers do every day."

"I understand the importance of yesterday's events and the role we played," he said. "I am grateful for the recognition we have received."

Contributing: Hannan Adely and Joe Malinconico, Paterson (N.J.) Press